Establishing best practices on the production, the processing and the marketing of meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) : final report.
Date: 2021-03-29
Institutions: Directorate-General for Health and Food Safety
Subjects: EU Member State, animal welfare, farmer, livestock farming, marketing, pigmeat, supply chain, swine, veterinary medicine

European 
Commission

ESTABLISHING
BEST PRACTICES

on the production, 
the processing 
and the marketing 
of meat from 
uncastrated pigs 
or pigs vaccinated 
against boar taint 
(immunocastrated)

Final report

14 March 2019

Health and
Food Safety

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Luxembourg: Publications Office of the European Union, 2019

© European Union, 2019

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PDF 

ISBN 978-92-79-99366-4 

doi:10.2875/541755 

EW-04-19-071-EN-N

EUROPEAN COMMISSION 

Acknowledgements 

This report was authored by ICF (Stefania Chirico, Kate McEntaggart, Julien Etienne, Yann 
Verstraeten, Andrew Jarvis, Aileen Corrieri) supported by a core team of experts (Katharina 
Stärk,  Daniel  Mörlein,  Jürgen  Hijink,  Heleen  van  de  Weerd,  Jos  van  Thielen,  Sanne 
Vanbeirendonck, Astrid Stampe Lovelady, Marjeta Candek Potokar, Antonio Velarde, Cecilia 
Pedernera,  Kristin  Djuve,  Anaïs  Léger).  Illustrations  were  produced  by  ICF  Mostra.  The 
contributions  of  stakeholders  who  responded  to  the  consultation  on  the  documents 
produced are gratefully acknowledged. The study team would also like to thank Gé Backus 
and the members of the study’s Advisory Board for their advice and contributions.   

2018 

Directorate-General for Health and Food Safety 

EUROPEAN COMMISSION 

Establishing best practices on 
the production, the processing 
and the marketing of meat 
from uncastrated pigs or pigs 
vaccinated against boar taint 
(immunocastrated)  
- 
Final report 

2018 

Directorate-General for Health and Food Safety 

Establishing best practices on the production, the processing and the marketing of 
meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

Table of Contents 

Executive summary ........................................................................................1 
1  Introduction ...............................................................................................8 
2  Subject and context of the study ..................................................................9 

2.1 Strategic context of the study .............................................................9 
2.2 Topics addressed by this study .......................................................... 10 

3  Methodology ............................................................................................ 11 

3.1 Task 2: Collecting data and observation ............................................. 12 
3.2 Task 3: Drafting of elements of best practices ..................................... 17 
3.3 Task 4: Consulting stakeholders on elements for best practices ............. 19 

4  Deliverable 1: Work plan............................................................................ 25 
5  Deliverable 2: State of play ........................................................................ 27 

5.1 Practices at farm level ...................................................................... 28 
5.2 Practices at slaughtering and processing level ..................................... 39 
5.3 Practices at retailing and food service level ......................................... 48 
5.4 Summary of initial findings and results of the data gathering ................ 54 
5.5 Description of problems encountered and solutions found ..................... 55 

6  Deliverable 4 (1) – Consultation process ...................................................... 56 
7  Deliverable 4 (2) - Final best practices ......................................................... 57 

7.1 Q1. Farmers – uncastrated pigs: management techniques .................... 57 
7.2 Q2. Farmers – vaccinated pigs: vaccination process ............................. 64 
7.3 Q3. Farmers – vaccinated pigs: provide assurance to slaughterhouses 

that vaccinated pigs do not present detectable boar taint ............... 71 

7.4 Q4. Slaughterhouses – uncastrated pigs: detect boar taint, quantify and 

manage positive carcasses ......................................................... 76 

7.5 Q5. Slaughterhouses – vaccinated pigs: obtain assurance from farmers 

that vaccinated pigs do not contain detectable boar taint ............... 87 

7.6 Q6. Food processors – vaccinated pigs: promoting meat from vaccinated 

pigs………………………………… ........................................................... 90 

7.7 Q7. Retailers and food services – uncastrated pigs: promoting meat from 

uncastrated pigs……………. ........................................................... 92 

7.8 Q8. Retailers and food services – vaccinated pigs: promoting meat from 

vaccinated pigs………………. .......................................................... 96 

8  Conclusions .............................................................................................. 99 
Annexes .................................................................................................... 101 

Annex 1 Terms of reference ................................................................. 102 
Annex 2 Data collection protocol ........................................................... 112 
Annex 3 List of presumptive good practices to be included in the data 

collection template………….. ....................................................... 113 
Annex 4 Model for the data collection template ....................................... 116 
Annex 5 Consultation – Feedback received from the European Commission 

and through the online platform ............................................... 117 
Annex 6 Consultation – Advisory Board .................................................. 152 
Annex 7 References………. ..................................................................... 165 

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Executive summary 

Introduction 

The  castration of  male  piglets is  a  routine  and  long-standing  practice in  pig  husbandry, 
common across most countries in the European Union (EU). It is, however, considered to 
be poor practice from an animal welfare perspective.  

Piglet castration is largely used as a method to avoid boar taint. Boar taint is an unpleasant 
odour or taste caused by the accumulation of two naturally occurring chemical compounds 
(skatole  and  androstenone)  in  the  tissues  of  uncastrated  males.  These  compounds 
contribute  both individually  and  in  combination  to the  perception of  boar  taint,  which  is 
observed during the cooking and consumption of pork. The challenge posed by boar taint 
to the pig meat sector complicates any move away from surgical castration, despite welfare 
concerns.  

There are two main options available for transitioning away from surgical castration. One 
is  to  raise  entire  male  pigs,  or  boars.  The  other  is  the  use  of  a  vaccine  that  blocks  the 
hormone  responsible  for  the  release  of  gonadotropins  (GnRH)  and suppresses  testicular 
function. Vaccination against boar taint requires that farmers are appropriately trained in 
using the vaccine and its use comes with its own costs and challenges.  Supply chains in 
some countries have begun the transition, by raising entire males or vaccinating pigs, or 
both,  but  surgical castration  is  still the norm for  pig  farming  in  the  majority of  Member 
States.  

This  study  identifies  best  practices  used  in  production  and  across  the  supply  chain  in 
relation to the raising and slaughter of entire males or pigs vaccinated against boar taint, 
and the processing and marketing of meat from such animals. It focuses solely on practices 
that have been trialled and successfully used in commercial conditions rather than looking 
at presumed best practices, trials or future initiatives. The study builds on work previously 
undertaken by the European Commission looking at the economic feasibility of a transition, 
the challenge of detection and consumer acceptance of alternatives to surgical castration. 

Best  practices  were  identified  at  different  points  in  the  supply  chain.  At  farm  level, the 
study  has  considered  best  practices:  to  reduce  boar  taint  in  entire  males  through 
management  techniques  on  farm;  to  vaccinate  pigs  against  boar  taint;  and  to  provide 
assurance to slaughterhouses that vaccinated pigs do not present detectable boar taint. At 
slaughterhouse level, the project addressed best practices: to detect boar taint, quantify 
and manage positive carcasses; to obtain assurance from farmers that vaccinated pigs do 
not  contain  detectable  boar  taint;  and,  to  deal  with  meat  with  detectable  boar  taint.  At 
retail and food service, best practices were identified to increase the market value of meat 
from uncastrated pigs and to promote meat from vaccinated pigs. 

Method 

The project began with an inception phase during which the team conducted preliminary 
research and consulted with experts to develop a long list of best practices. This long list 
was then used to inform development of a data collection template. Country researchers 
used the template to collect information through desk and field research in seven Member 
States  (Belgium,  Denmark,  France,  Germany,  the  Netherlands,  Spain  and  the  UK)  and 
Norway. These countries  were  chosen on the  basis  that  each had  some  experience  with 
either raising entire males or with vaccination against boar taint.  

The purpose of the country research was not only to identify best practices within each of 
the  topics,  but  also  to  verify  that  these  best  practices  were  occurring  in  commercial 
conditions.  Researchers  contacted  a  range  of  stakeholders  during  this  period,  including 
farmers, slaughterhouses, food processors, retailers and food service operators, as well as 
quality assurance companies, breeding companies, feed producers, laboratories that have 
developed  techniques  for  boar  taint  detection  and  vaccine  suppliers.  Data  were  largely 

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from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – Final 
report 

gathered  through  phone  interviews  and  email  exchanges.  Visits  were  made  to 
slaughterhouses, a farm and a breeding company in Germany and the Netherlands.  

The  results  of  the  country  research  were  collated  and  reviewed  by  the  project  team  to 
identify  what  could  be  considered  best  practice.  A  ‘state  of  play’  document  was  drafted 
that identified what practices are occurring where and what gaps remained. The results of 
the country research were then used in the drafting of a set of elements of best practice. 
These documents were prepared by a team of non-specialists with excellent writing skills 
and reviewed by subject matter specialists.  

An online consultation platform was launched and all contributing stakeholders were invited 
to comment on the draft elements of best practice documents. Stakeholders could either 
comment directly on the platform or provide feedback to the team via email.  

The feedback was collated and reviewed. In some instances, the study team followed up 
with stakeholders to clarify comments or gather additional information. The draft elements 
of practice were then revised based on these comments.  

The draft documents were presented to two meetings of an advisory board consisting of 
stakeholders  from  across  the  supply  chain.  The  advisory  board  meetings  were  used  to 
discuss the feasibility of various practices and provide context on some of the outstanding 
comments from the online consultation. The text was revised based on feedback from the 
advisory board meetings and final versions of the elements of best practice were prepared 
for inclusion in the final report. 

State of Play 

Many  of  the  challenges of  switching to production of  entire males  or vaccination  against 
boar taint relate to supply chain dynamics and relationships. For example, the costs and 
benefits of a transition to production without castration are not distributed equally between 
different participants in the supply chain. Switching to production of entire males results 
in changes to the costs incurred by the farmer, the feed producer, and the slaughterhouse. 
To incentivise change, these shifts in distribution of cost need to be recognised across the 
chain.  This  can  be  done  through  slaughterhouses  or  end-buyers  offering  premiums  to 
farmers to cover the additional costs of using specific breeds of animals and specific feed 
to reduce the incidence of boar taint. Often, however, the additional costs are borne largely 
by the farmers themselves. Where supply chains are highly integrated, this is less of an 
issue.  Where  they  are  not,  much  depends  on  the  relationship  between  slaughterhouses 
and farmers, which in many countries tends to be characterised by low trust. 

A bonus-malus system1 related directly to the presence or absence of boar taint is one way 
of incentivising farmers to take up more preventative practices, and pass on some part of 
the economic loss incurred by the slaughterhouse as a result of the presence of detectable 
boar taint in a carcass. Such a system, linked to boar taint detection, is used in France. 
There  are  other  bonus-malus  systems  in  which  penalties  are  based  on  weight  or  are 
universal  for  all  boars.  The  fact  that  boar  taint-based  financial  incentives  are  not  more 
widespread is ascribed largely to the subjective character of existing tests and the lack of 
trust between farmers and slaughterhouses. 

Demand  is  the  key  driver  for  transition:  ultimately,  a  transition  to  entire  males  or  pigs 
vaccinated against boar taint can only occur where there is an end market for meat from 
these pigs. For most supply chains in Europe, this means that a transition can only occur 
where retailers and food services are willing to sell such meat.  

1 An incentive system that is designed to give positive reward for good performance, and impose a penalty for poor 
performance. 

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Practices at farm level 

The  prevalence  of  non-castration  and  vaccination  practices  varied  across  countries. 
Uncastrated  pigs  are  commercially  produced  in  all  the  countries  studied  in  this  project, 
with the exception of Norway. In some countries (such as Spain and the UK), production 
of entire males is well-established.  

Vaccination  against  boar  taint  is  not  widely  practised  in  Europe,  meaning  that  the 
information received came from a small number of countries and sources. Belgium has the 
most  experience  with  vaccination.  Spain  and  the  Netherlands  also  reported  some  use. 
Norway had previously trialled the use of vaccination commercially, but it is no longer being 
used as frequently.  

A  wide  range  of  practices  was  found  at  farm level  for  both  raising  entire  males  and  for 
dealing  with  vaccination  against  boar  taint.  Many  of  these  practices  were  also  already 
documented in the literature.  Several feeding solutions were identified, and a number of 
them are commercially available. Although these are associated with raising entire males, 
feeding practices to reduce taint could also be used for pigs vaccinated against boar taint.  

There are additional costs associated with many of these options but both entire males and 
vaccinated  pigs  have  been  shown  to  have  more  efficient  feed  conversion  ratios  than 
surgically castrated males. Previous research has estimated that the better feed conversion 
is worth €7.11 per pig for entire males and €6.10 for vaccinated pigs.  

The timing of slaughter, referenced either to weight or age, is used almost universally to 
manage the risk of boar taint. The exact weight thresholds vary depending on country and 
source. 

Research  has  looked  at  using  breeding  and  genetics  to  reduce  boar  taint  incidence. 
Breeding techniques are used at a commercial level in several countries.  

The practices identified for reducing boar taint through modifying how the pigs are housed 
were  all  general  practices  associated  with  improved  welfare.  These  practices  are  well 
documented, although it is not clear to what extent they impact boar taint prevalence.  

Although  vaccination  against  boar  taint  is  not  yet  widespread  in  Europe,  substantial 
information  on  the  practice  was  available  through  the  detailed  guidance  provided  by 
vaccine  suppliers.  Practices  related  to  vaccination  were  also  confirmed  by  farmers. 
Information  providing  assurance  that  vaccination  has  worked  was  provided  by  vaccine 
suppliers and confirmed by farmers. 

Practices at slaughtering and processing level 

Some  information  on  slaughtering  and  processing  was  available  from  previous  research 
but there was less relevant literature on these practices than for farm level actions. Most 
slaughterhouse practices focused on detection. Some detection practices were unique to 
vaccination against boar taint, although many of the practices identified for detecting boar 
taint in entire males may also be used for vaccinated pigs.  

Some examples were found of supply chains raising entire males that do not use detection 
methods. In the UK, boars are slaughtered at a lower weight (105-110 kg) to manage the 
risks  of  boar  taint.  In  Spain,  boar  taint  is  addressed  entirely  through  processing  and 
masking.  

The research located one example of a chemical testing device being used. Some examples 
were  identified  of  new  and  promising  chemical  testing  techniques  currently  under 
development, but none of these are currently available commercially.  

The  most  popular  detection  method  among  slaughterhouses  was  some  variation  of  the 
human nose method. The most common of these are on-line methods, where some type 
of welding equipment (including hot air devices, soldering irons with metal tips and gas-
powered soldering irons) is used to heat the meat on the slaughter line and the operator 

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then smells it to try to detect boar taint. Two off line methods, the hot water method and 
the microwave method, were also found to be in use. Both involve taking a sample of fat 
from  the  carcass  and  taking  it  to  a  separate  testing  area  on  site.  Off  line  methods  are 
generally more suitable for slaughterhouses that process fewer boars and as quality control 
methods.    Operators  use  several  different  methods  to  promote  consistency  of  detection 
when using human nose methods. External consulting firms are frequently used to provide 
training and assessment of operators, and in some instances external contractors are also 
used for in-house testing.  

Several supply chain management practices were identified. There have been some efforts 
to establish frameworks or protocols for human nose testing, notably a harmonised effort 
between  quality  assurance  companies  in  Germany  (QS)  and  in  the  Netherlands  (IKB). 
Some  slaughterhouses  have  established  logistical  agreements  with  suppliers  whereby 
boars and gilts are provided in separate batches, which can help to make the boar taint 
detection process more efficient and keeps different types of carcass apart.  

Some slaughterhouses provide feedback to farmers on boar taint prevalence. The protocol 
established  by  QS  and  IKB,  for  example,  requires  all  slaughterhouses  engaged  in 
processing entire males to do so. Although some slaughterhouses had systems in place for 
monitoring complaints, no slaughterhouses reported having received complaints related to 
boar taint.  

Carcasses that tested positive for boar taint were generally sold into specialist markets or 
used for processed meat products.  

Several  potential  practices  were  identified  for  helping  slaughterhouses  to  ensure  that 
vaccinated  pigs  do  not  contain  boar  taint.  Practices  that  involve  measuring  the  size  or 
weight of sexual organs, including the testes and the bulbourethral gland, were reported 
in to be in use but were felt by many stakeholders to be largely ineffective and difficult to 
implement.  Random  checks  for  boar  taint  were  considered  preferable,  and  such  tests 
generally used similar methods to the detection tests for entire males.  

Testosterone  tests  can  be  used  on  batches  of  pigs  to  identify  at-risk  carcasses.  This 
approach  was  recommended  by  the  vaccine  manufacturer  and  has  been  used  by  some 
slaughterhouses.  

Several options were identified for processing meat that has detectable boar taint. These 
practices differ between countries; their practicality ultimately depends on local processing 
practices and the perceived consumer sensitivity to boar taint within a Member State. In 
Germany stakeholders  reported  that  dilution, fermentation  and  smoking of tainted meat 
are used to mask boar taint in the final product. Thermal treatment is used by processors 
in both Germany and Spain. Spices are used in Spain to mask boar taint while marinating 
tainted meat. Dilution is used in Denmark. 

Practices at retailing and food service level 

It  was  difficult to identify  practices  in retail  and  food  service  relating to management  of 
boar taint in entire males or in pigs vaccinated against boar taint. There was little available 
information in the literature and companies are generally unwilling to communicate about 
this issue.  

Practices at retailing and food service level are largely dictated by firms’ understanding of 
the  consumer  acceptance  of  boar  taint.  There  has  been  some  exploration  of  this  in  the 
literature through  cross-country or single-country studies looking for  potential threshold 
values for androstenone and skatole. 

Many consumers are not aware of piglet castration and boar taint. A few examples were 
identified  of  retailers  using  marketing  campaigns that  emphasise  animal  welfare  and  do 
not  mention  piglet  castration  specifically.  Many  of the campaigns used to  promote  meat 
from  entire  males  use  specific  labels  related  either  to  a  specific  assurance  scheme  or 
product  line.  One  example  was  found  of  a  retailer  campaign  for  a  product  line  that 

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emphasised not only animal welfare, but also potential environmental and human health 
benefits related to non-castration.  One example was found of a producer working in close 
collaboration with a retailer to conduct in-store trials of meat from entire males.  

Customer  complaints  could  help  monitor  the  effectiveness  of  measures  implemented  to 
prevent boar tainted meat from reaching consumers. However, no evidence was found of 
retailers using this practice to address boar taint.  

Elements of best practice 

Best practices were identified at each stage of the supply chain.  

Farmers – uncastrated pigs: management techniques  

Learning  to  manage  boars  was  included  as  a  farm-level  practice,  as  entire  males  have 
different needs and are more likely to display aggressive or sexual behaviour. 

Several practices related to flooring and housing were identified. Keeping pigs clean and 
dry is included as a practice that can help to reduce skatole levels. Slatted floors are cited 
as  one  way to  improve hygiene. Sex-separated  rearing  and  wean-to-finish  grouping  are 
listed  as  housing  practices  that  may  help  to  reduce  stress  levels.  Several  additional 
practices  are  identified  under  the  umbrella  of  “low-stress  environments”.  Practices  to 
reduce competition at feeding, including wet feeding, are also included as they can help to 
reduce stress.  

Two  different  options  are  included  under  breeding  practices.  One  is  choosing  specific 
breeds, such as the Piétrain, which are less likely to test positive for boar taint. The other 
is selective breeding techniques: breeding companies use special techniques to select for 
low taint boars. 

Several options are identified for reducing boar taint prevalence through the adjusting the 
composition of the  animals’  feed.  Chicory  root can  be  used  as  an  additive  and has  been 
shown to reduce skatole levels. Diets with adjusted amino acids are included as a way to 
increase  the growth of entire males  so that slaughter  occurs  at  a  younger  age.  Protein-
reduced diets can be used in the few days prior to slaughter to reduce skatole levels. This 
is considered a low cost and highly feasible solution. Some commercially-available feeds 
designed to reduce boar taint were also identified.  

Scheduling  slaughter  at  a young  age is  also  included  as  method for  reducing the risk of 
boar taint.  

Farmers – vaccinated pigs: vaccination process 

Information  is  provided  on  the  vaccination  principle,  which  includes  background 
information on the efficacy and cost of the vaccine. The vaccination procedure is included 
as a best practice, with details on the correct positioning and how to minimise stress. The 
use  of  a  dosing  gun  and  protective  clothing  are  both  listed  as  best  practices  for  the 
implementation of the vaccine. 

Information  on  scheduling  the  vaccination  is  provided.  This  includes  the  main  protocol, 
describing  the  general  timing  of  the  first  and  second  vaccinations  and  a  compliance 
inspection.  Early  vaccination  is  included  as  a  practice  that  can  be  used  to  maximise 
intramuscular fat and back fat. Late vaccination is included as a practice that can be used 
to achieve a better feed conversion and leaner carcasses. Using three doses for larger pigs 
is included as a practice to raise vaccinated pigs to heavier weights.  

Practices  for  feeding  vaccinated  pigs  are  described,  included  details  related  to  lysine 
requirements and feed conversion. 

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Farmers – vaccinated pigs: provide assurance to slaughterhouses that vaccinated 
pigs do not present detectable boar taint  

Some  of  the  farm  level  practices  included  relate  to  promoting  trust  in  the  vaccination 
process. On-farm checks of pig behaviour are described (vaccinated pigs behave noticeably 
differently  from  entire  males).  Supply  chain  assurance  practices  are  also  described, 
including  the  use  of  documentation  to  record  and  communicate  details  of  vaccination 
procedures to other members of the supply chain.   

Slaughterhouses  –  uncastrated  pigs:  detect  boar  taint,  quantify  and  manage 
positive carcasses  

The  practices  included  at  slaughterhouse  level  to  detect,  quantify  and  manage  positive 
carcasses principally relate to use of the human nose method. The principle of the human 
nose method is described, indicating the purpose of the method and where fat should be 
sampled.  Four  main  variants  are  included:  the  hot  air  /  hot  iron  method  and  the  gas-
powered soldering iron (both on line methods) and the hot water method and microwave 
method (both off line methods). 

Two scales for measuring boar taint are included. The human nose method can be used 
with either a binary (taint/no taint) approach or a scale with multiple levels (such as 1-5) 
to indicate the intensity of boar taint presence. Both methods require special training and 
consistent application.  

Practices  for  selecting  and  training  testers  are  discussed.  Several  service  providers  in 
different  Member  States  are  available  to  assist  slaughterhouses  with  training  and 
implementation.  

Best  practices  for  quality  control  are  identified.  These  include  using  multiple  testers, 
conducting  parallel  controls  and  using  statistical  analysis  to  investigate  possible 
inconsistencies. As humans are prone to smell habituation, two practices to prevent this 
are included: taking regular breaks and using nose cleansers (such as menthol or coffee) 
to reset the sense of smell. 

Protocols  for  harmonising  human  nose  testing  across  supply  chains  are  listed  as  a  best 
practice and an example of a framework in use is presented.   

Non-detection is identified as a best practice, where cut-off weights or masking are used 
to minimise the risk for boar taint.  

Several  practices  were  identified  relating  to  supply  chain  management.  These  include 
keeping  records  and  providing  feedback  to  farmers,  penalties  for  boar  taint,  conducting 
farm audits and accepting pigs in same-sex groups.  

Two main practices were identified for classifying carcasses with boar taint. One focuses 
on electronic classification systems and the other on the manual classification of carcasses 
(use of physical markers to distinguish between tainted and non-tainted carcasses).  

Slaughterhouses  –  vaccinated  pigs:  obtain  assurance  from  farmers  that 
vaccinated pigs do not contain detectable boar taint  

Best  practices  for  use  by slaughterhouses  to  ensure that  vaccinated  pigs  do not contain 
detectable  boar  taint  include  checks  to  verify  that  vaccination  has  been  administered 
correctly. This can be important for less experienced slaughterhouses and farmers to gain 
confidence in the vaccination against boar taint. Three different practices are described: 
the human nose method, a blood test for testosterone and chemical testing of a fat sample.  
This section also discusses the use of bonus payments for vaccinated pigs.  

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Food processors – uncastrated pigs: deal with meat with detectable boar taint  

The report identifies a variety of processing practices that can be used to deal with meat 
with detectable boar taint. Many of these practices may be suitable for use in combination 
with each other.  

Using tainted meat for products intended to be consumed cold is a commonly used practice 
as boar taint is most noticeable during the cooking or heating of meat. Dilution or mixing 
with non-tainted meat is used for products that do not come from a single cut of meat. Dry 
curing, fermentation, smoking and thermal treatment are all ways of processing or cooking 
pig meat that can help to reduce the perception of boar taint. Using spices for sausages or 
for marinated meats is also included as a practice to reduce the perception of boar taint.  

Retailers and food services – uncastrated pigs: promoting meat from uncastrated 
pigs    

Several  practices  were  identified  for  use  by  retailers  and  the  food  service  industry  to 
promote  meat  from  uncastrated  pigs.  Marketing  techniques  include  various  types  of 
campaigns.  Some  emphasise  animal  welfare  benefits,  others  include  animal  welfare 
benefits alongside environmental or human health benefits. 

Buyer specifications are included as a practice to encourage other parts of the supply chain 
to make the transition. During the transition, practices such as visits, information sharing 
and the certification of boar taint detection methods can be used to build trust within the 
supply chain. In-store trials are also listed as a practice that retailers can use to ensure 
that  meat  from  uncastrated  pigs  is  accepted  by  consumers.  The  use  of  animal  welfare 
labels or other types of assurance schemes is included as a practice to add value to meat 
from entire males.  

Retailers and food services – vaccinated pigs: promoting meat from vaccinated 
pigs  

Similar practices were identified for retailers and the food service industry to promote meat 
from vaccinated pigs. Marketing campaigns can also be used, emphasising animal welfare, 
health  and  sustainability.  Farmer  management  can  be  used,  and  retailers  may  wish  to 
enact farm-level controls or to provide training to contracted farmers on the vaccination 
against boar taint.   

Conclusions 

While EU production of entire males and vaccinated pigs remain small by comparison with 
the  overall  production  of  pig  meat,  it  involves  major  operators  that  have  invested 
considerable  resources,  expertise,  and  effort  to  find  solutions  that  work  not  only  within 
individual organisations,  but  across  whole  supply  chains.  Evidence  from  these  operators 
demonstrates  that  it  is  commercially  feasible  to  transition  from  physical  castration  to 
raising entire males or vaccinating them against boar taint. While improving pigs’ welfare 
significantly,  these  changes  have  also  resulted  in  increased  profitability  for  some 
businesses.  

The  practices  documented  in  this  study  show  that  solutions  require  coordination  and 
information exchange between different actors of the supply chain. Change has happened 
through exchange of good practices, data sharing, and agreements on how to share the 
costs and the benefits of changes to the mode of production. Successful transitions have 
occurred where initiators have demonstrated to commercial partners that a different way 
of  working  is  feasible,  robust,  and  safe.  Together,  these  individual  practices  provide  a 
compelling  portfolio  of  options  for  supply  chains  interested  in  making  a  transition  away 
from surgical castration. 

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1 

Introduction 

This is the final report for the “Establishing best practices on the production, the processing 
and  the  marketing  of  meat  from  uncastrated  pigs  or  pigs  vaccinated  against  boar  taint 
(immunocastrated)2”  as  contracted  by  the  European  Commission  –  DG  SANTE  (project 
reference: SANTE/2018/G2/049/SI2.775309).  

The purpose of this study has  been to contribute  to  a  decrease in the  need  for  surgical 
castration  of  piglets  in  the  EU  through  knowledge  transfer.  Specifically,  it  identifies  and 
explains best practices that contribute to this objective, looking at all stages of the food 
chain, from farming to retail. 

This report presents: 

  The context for the study (section 2);  

  The methodology (section 3) and workplan (section 4) for collecting data and 

drafting best practice documents; 

  The state of play of existing practices for vaccinating pigs against boar taint and 

raising entire males (section 5);  

  The results of the consultation process (section 6) and the final best practices 

(section 7); and 

  The study conclusions (section 8).   

This final report is the fourth report required under this contract and builds on the interim 
report,  results  of  stakeholder  consultations  and  feedback  on  the  draft  final  report.  This 
report  presents  updated versions  of  Deliverables  1  (work plan)  and 2  (state of  play).  It 
also includes Deliverable 4 (consultation process and final best practices in English).  

2 For the purpose of this study, the terms “vaccination against boar taint” and “immunocastration” are considered to be 

equivalent. 

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2 

Subject and context of the study 

2.1  Strategic context of the study 

The  castration  of  male  piglets  is  a  routine  and  long-standing  practice  in  pig  husbandry, 
common  across  most  countries  in  the  EU.  Castrating  piglets  is  considered  to  be  poor 
practice  from  an  animal  welfare  perspective.  This  is  recognised  by  Council  Directive 
2008/120/EC, which cites the need for better practices and EU-level action and states:  

"Castration is likely to cause prolonged pain which is worse if there is tearing of the tissues. 
Those practices are therefore detrimental to the welfare of pigs, especially when carried 
out by incompetent and inexperienced persons."3 

Piglet castration is largely used as a method to avoid boar taint. Boar taint is an unpleasant 
odour  caused  by  the  accumulation  of  skatole  and  androstenone  in  the  tissues  of 
uncastrated  males.  These  compounds  contribute  both individually  and  in  combination to 
the perception of boar taint, which is described as resembling urine and manure, as well 
as  mothballs,  sweat  and  "pig".    Sensory  perceptions  of  boar  taint  differ,  however,  and 
studies have shown that a sizeable proportion of consumers are not sensitive to boar taint.  
Boar taint is generally observed during the cooking and consumption of pork. The challenge 
posed  by  boar  taint  to  the  pig  meat  sector  complicates  any  move  away  from  surgical 
castration, despite welfare concerns. The observed need for action on pig castration led to 
the establishment of the European Declaration on alternatives to surgical castration of pigs 
in 2010. The declaration has been signed by industry and farmers groups, as well as animal 
welfare NGOs across Europe. The intention of the Declaration and subsequent partnership 
is to phase out the surgical castration of pigs by January 1st, 2018 and ensure the costs 
of this transition are shared.  

There are two main options available for transitioning away from surgical castration. The 
first option is raising entire male pigs, or boars. Raising entire males requires changes to 
standard practice that can help minimise the risk of boar taint. The second option is the 
use  of  a  vaccine  that  blocks  the  hormone  responsible  for  the  release  of  gonadotropins 
(GnRH)  and  suppresses  testicular  function.  Vaccination  requires  that  farmers  are 
appropriately  trained  in  using  the  vaccine  and  its  use  comes  with  its  own  costs  and 
challenges.  

Supply chains in some countries have begun the transition to raising either entire males, 
vaccinated  pigs  or  both,  but  surgical  castration  is  still  the  norm  for  pig  farming  in  the 
majority of Member States. As such, this study highlights best practices at different stages 
of  production  and  across  whole  supply  chains  that  are  currently  used  when  raising, 
slaughtering,  processing  and  marketing  meat  from  entire  males  or  vaccinated  pigs.  It 
builds on work previously undertaken by the European Commission looking at the economic 
feasibility  of  a  transition,  the  challenge  of  detection  and  consumer  acceptance  of 
alternatives  to  surgical  castration.  However,  rather  than  looking  at  presumed  best 
practices, trials or future initiatives, this study focuses solely on practices that have been 
trialled and successfully used in commercial conditions.  

3 Council Directive 2008/120/EC of 18 December 2008 laying down minimum standards for the protection of pigs 

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2.2  Topics addressed by this study 

This study addresses practices at farming, slaughterhouse, processing and retail/marketing 
levels for both entire males and vaccinated pigs. The issues covered by the study, as listed 
in the terms of reference, are presented in Table 1.  

Table 1. 

Issues to be addressed by this project, as requested by the terms of reference 

Target 
audiences 

Farmers 

Uncastrated pigs 

Q1- Techniques and best 
practices to reduce boar taint 
through management techniques 
(including feeding and breeding) 

Pigs vaccinated against boar 
taint 

Q2- Techniques and best 
practices to use the vaccine in 
various type of pigs  

Q3- Techniques and best 
practices to ensure to 
slaughterhouses that vaccinated 
pigs do no present detectable 
boar taint  

Slaughterhouse 
operators 

Q4- Techniques and best 
practices to detect boar taint, 
quantify and manage positive 
carcasses  

Q5- Techniques and best 
practices to trust farmers that 
vaccinated pigs do not contain 
detectable boar taint  

Food processors  Q6- Techniques and best 

Not relevant 

Retail and food 
services 

practices to quantify and deal 
with meat with detectable boar 
taint  

Q7- Techniques and best 
practices to increase the market 
value of meat from uncastrated 
pigs and to prevent meat with 
detectable boar taint to be on the 
shelves or served. 

Q8- Techniques and best 
practices to increase the 
acceptance of meat from 
vaccinated pigs among 
consumers and to prevent meat 
with detectable boar taint to be 
on the shelves or served. 

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3  Methodology 

This section presents the project methodology. Figure 1 presents the study workflow. 

Figure 1.  Overview of the work 

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3.1  Task 2: Collecting data and observation 

3.1.1  Purpose 

The aims of this task were to: 

  collect information on the existing practices relevant to the study; and  

  analyse the information collected and identify gaps. 

This task examined the existing situation and current practices, covering all the questions 
identified in the terms of reference (as listed in Table 1).  

The data collection task built on scoping research undertaken for Task 0 (Inception) and 
Task 1 (Updated methodology and work plan). The scoping research involved a targeted 
literature review, and brief phone discussions with members of our expert team and other 
chosen  experts  who  have  published  relevant  works  on  the  issues  presented  in  Table 1. 
Findings from scoping research resulted in an initial list of practices that might be in use 
commercially to address these issues, to be further investigated with data collection. 

For  Task  2,  in-depth  information  was  collected from selected  Member States.  The  team 
also included putative best practice documents from other EU countries and third countries 
when they were brought to the team’s attention. 

The purpose of this task was not only to identify presumptive best practices, that is, 
practices that appear to have  distinct advantages  from an animal welfare and economic 
point  of  view,  but  also  to  verify  that  presumptive  best  practices  identified  at  the 
inception stage are practiced in commercial conditions. 

Existing  practices  and  any  evidence  on  their  advantages  and  disadvantages  were 
documented.  Data  collection  and  observations  informed  the  drafting  of  best  practice 
elements in Task 3. 

Box 1  Member States selected for the study 

As part of the terms of reference, the study team was requested to collect information from six 
Member States: Belgium, Denmark, France, Germany, the Netherlands and Spain. The UK and 
Norway were selected as additional countries for the research.  

The UK has been producing entire males for a very long time and as such is a source of information 
on proven techniques and good practices across the whole supply chain.  

Norway  has  a  well-established  supply  chain  for  vaccinated  pigs.  Norway  provided  a  useful 
counterpoint  to  Belgium,  the  other  country  in  which  vaccination  against  boar  taint  has  been 
demonstrated at the proof of concept stage. 

Towards the end of the study an additional enquiry was made about the production of Parma ham 
in Italy using vaccination. 

3.1.2  Method 

Stakeholder  groups  –  farmers,  slaughterhouses,  food  processors,  retailers  and  food 
service operators – were identified through: 

  Identification  of  relevant  contacts  in  the  personal  and  professional  networks  of 

members of the study team (in particular, the team’s country experts);  

  Expansion  of  the  initial  network  through  a  snowballing  approach  (one  contacted 
stakeholder providing the contact details of another, relevant stakeholder); and 

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  Additional  contact  details  being  obtained  via  approaches  to  representative 

associations of the different groups of stakeholders. 

ICF  offered  confidentiality  to  all  stakeholders  to  address  concerns  arising  from  the 
sensitivity of the topic and the potential disclosure of commercially-sensitive information. 

The study team also approached some other actors who are involved in the supply chain 
in specific roles and were able to supply relevant information. They were: 

  Quality assurance companies; 

  Breeding companies that are working specifically on selecting animals based on 

boar taint; 

  Feed producers manufacturing dedicated feed solutions; 

  Laboratories that have developed techniques for boar taint detection; 

  Suppliers of vaccines against boar taint. 

The collection of evidence in  each country was conducted  in an official language of that 
country. 

In  task  2  the  project  team  collected  information  on  practices  that  are  observable  in 
commercial  conditions.  To  ensure  a  consistent  approach  across  countries,  all 
researchers followed standard instructions and templates for data collection (see Annex 1 
and Annex 3).  A systematic check was applied to each presumptive best practice, with a 
requirement that each practice was linked to at least one commercial operation setting in 
the EU. 

3.1.3  Task 2.1: Desk research 

Desk research on possible best practices was conducted through the following steps: 

  collection  of  documents  already  known  to  the  project  team  members  in  their 

capacity as experts on the various subjects covered by the research; 

 

 

identification of other publicly available documents; and 

the  despatch  of  email  request  for  additional  documentary  evidence  to  key 
stakeholders.  An  accreditation  letter  by  DG  SANTE  accompanied  this  email.  The 
email also included a request to provide contacts of additional stakeholders.  

An inventory of the relevant documents collected through desk research was produced (see 
Annex 7).  

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Table 2.  Desk research protocol 

Criteria 

Details 

Document 
types 

The search covered the following document types: 

Best practice and guidance documents 

Standard operation procedure (SOP) documents (for slaughterhouses) 

Quality standards (in supply chains) 

National literature on existing practices (all EU sources, especially those 
from research projects, were reviewed as part of Task 1) 

Sources 

Web search: 

National competent authorities 

National industry associations 

National professional news  

Sites of individual businesses (producers, slaughterhouses, processors, 
retailers, food service operators, breeders, feed producers) 

Language 

English and the national languages of the case study Member States 

3.1.4  Task 2.2: Contacts with Member State stakeholders 

Selected stakeholders were contacted for this phase of the research. For individual experts 
and  businesses,  the  contacts  were  made  by  telephone  and  face-to-face.  Business 
organisations were also contacted by email as a supplementary measure. 

Telephone enquiries were designed to: 

  Verify  that  the  information  collected  through  desk  research  reflected  existing 

practices and fill any gaps;  

  Collect information on any additional practices that were not identified through desk 

research; and 

  Discuss  practices  that  are  considered  particularly  beneficial  with  the  purpose  of 
identifying preliminary elements of best practices and potential business operators 
for field visits. 

These enquiries were supplemented, where possible, by an email exchange, whereby the 
results  of  the  desk  research  were  shared  with  stakeholders  for  fact  checking  and  to  fill 
gaps. 

Table 3 indicates the number of stakeholders consulted for this task. The variation in the 
number  of  stakeholders  consulted  by  country  and  stakeholder  group  reflects  the 
differences in production systems and practices used: for example, only a small number of 
operators  in few  countries  use  vaccination.  The  high  degree  of  market  concentration  in 
some  countries  (such  as  Denmark)  means  that  few  companies  are  operating  in  the  pig 
market. 

The  stakeholders  consulted  included  national  associations  and  research  organisations. 
Some  of  them  shared  information  from  ad  hoc  surveys  of  practices  associated  with 
vaccination and non-castration. Specifically: 

  In the UK, a farmer association launched a survey of its 300 members to enquire 

about management practices for boar taint; 31 answers were received.  

  In France, an association of meat processors launched a survey directed to its 250 
members, asking which type of pig meat they were sourcing and if they were dealing 

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with  tainted  meat.  Only  seven  organisations  responded  to  the  survey  (4  large 
companies – with more than 1,000 employees; 1 medium-sized firm – with between 
100 and 1,000 employees; and 2 small firms, – with fewer than 100 employees). 
Five  respondents  indicated  they  were  sourcing  their  meat  only  from  surgically 
castrated or vaccinated pigs, and two indicated they were sourcing a mix of meat 
from  both  castrated  and  non-castrated  animals.  Both  of  the  companies  that 
accepted  a  mix  of  castrated  and  non-castrated  pork  were  large  firms  (>  1000 
employees) that control incoming and outgoing products and conduct audits of their 
suppliers.  They  also  monitored  customer complaints about their products. One of 
these  manufacturers  produced,  among  other  products,  bacon,  which  is  highly 
sensitive to boar taint. 

  A  Norwegian  research  organisation  shared  the  results  of  a  survey  of  national  pig 
producers  about  their  attitude  to  and  experience  with  vaccination.  Of  the  430 
respondents, 134 of them had used vaccination against boar taint in their herd. 

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Table 3.  Number of stakeholders who positively responded to invitations to contribute, 

by country and stakeholder type for Task 2.2, and complementary data 
collection at the end of the consultation phase (Task 4) 

Stakeholder 
type 

BE 

DE 

DK 

ES 

FR 

NL 

NO  UK 

IT  Tot 

Farmers 

6 

Slaughterhouses  7 

13 

10 

Processors 

Retailers and 
food service 
operators  

Meat traders 

Quality 
assurance 
companies 

Breeding 
companies 

1 

3  

0 

0 

1 

Feed producers  1 

Companies 
providing boar 
taint detection 
services 

Vaccine 
suppliers 

Research 
institutes and 
experts  

Veterinarians 

Competent 
authorities 

0 

0 

0 

0 

0 

1 

1 

0 

0 

1 

1 

1 

0 

0 

0 

0 

0 

1 

2 

1 

0 

0 

0 

0 

0 

0 

2 

1 

0 

10 (1)  14 

4 (1)  1 

1 (1)  15 

37 (3) 

7 

14 

6 

1 (1) 

44 (1)  3 

3 (3) 

0 

0 

1 (1) 

0 

1 

0 

0 

1 

0 

0 

0 

0 

0 

1 

14 

0 

0 

1 

1 

1 

0 

0 

0 

1 

0 

1 

1 

0 

0 

1 

1 

1 

0 

0 

1 

0 

0 

0 

0 

0 

1 

0 

1 

0 

0 

3 

0 

1 

0 

1 

1 

0 

0 

15 

15 

0 

34 

15 (2) 

9 (4) 

0 

0 

1 (1) 

3 

0 

5 

0 

0 

4 

1 

0 

3 

0 

5 

0 

0 

2 

2 

Note: the numbers in brackets indicate how many, out of all stakeholders consulted, 
were representative associations 

3.1.5  Task 2.3: Preliminary visits in Member States 

Field visits provided opportunities to observe some of the practices and, in particular, those 
that were not documented in literature review. This helped to improve the robustness and 
completeness of data collection findings. 

Country  experts  and the  ICF  research team  assessed  the  potential case for undertaking 
field  visits  in  the  countries  covered  by  data  collection.  When  potential  field  visits  were 
identified, country experts contacted stakeholders and enquired about their availability for 

4 In France, one consultee integrates farmers, feed producer, slaughterhouses and processors. 

5 In Italy, a single consultee was interviewed, who represents an organisation integrating farming, slaughtering and 

processing. 

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a  visit.  In  case of unavailability,  data  was  gathered through  phone  interviews  and  email 
exchanges.  

Since field visits were undertaken on the basis of intelligence received on presumptive best 
practices,  they  were  unevenly  distributed  across  the  selected  Member  States.  Some 
stakeholders contacted for possible field visits were not available; others agreed, but were 
reluctant to share additional information to what was discussed by phone; therefore, a visit 
was not expected to bring additional value to the research.  

Field visits were conducted as described below. 

Germany:  

A  large  slaughterhouse  was  visited  to  witness  the  methods  used  to  deal  efficiently  with 
large numbers of entire males. 

The researcher visited a farm producing piglets in accordance with the terms of an animal 
welfare  scheme  that  supports  alternatives  to  physical  castration.  Feeding  and  breeding 
sizes for the production of entire males were discussed.  

A  breeding  company  was  visited  to  discuss  the  latest  developments  in  use  of  genetic 
selection for the reduction of boar taint. 

The Netherlands:  

A large slaughterhouse was visited to observe practices associated with the human nose 
method6  for  boar  taint  detection.  This  included  observing  the  detection  tools,  the 
implementation of the method, and how the slaughterhouse dealt with tainted meat. 

3.1.6  Task 2.4: Comparative analysis, synthesis and identification of gaps 

The data recording templates, once completed, were collated and reviewed by members 
of  the  project  team.  The  project  team  assessed  what  practices  were  observable  across 
countries and whether these addressed the questions listed in the terms of reference. 

The practices described were then  compared against the  initial list of practices that was 
developed  in  Task  1  based  on  the  broader  literature  (see  Annex  3).  This  comparison 
enabled the identification of gaps, where some research may exist but no or few practices 
have been observed on the ground. 

The results of this assessment are presented in section 4 (Deliverable 2).  

3.2  Task 3: Drafting of elements of best practices 

3.2.1  Purpose 

The purpose of this task was to develop a draft set of best practices based on Deliverable 
2. These were discussed and further developed through consultations with stakeholders in 
Task 4. 

3.2.2  Method 

The  drafting  and  review  of  the  documents  was  governed  by  a  set  of criteria  (explained 
below) that were intended to ensure the quality of the end product.  The drafting process 
was  led  by  non-specialists  with  excellent  writing  skills.  Their  outputs  were  reviewed  by 
subject matter experts (as detailed in section 3.2.3). 

The drafting criteria were:  

  Accuracy  –  the  text  should  provide  a  good  description  of  the  practice  that  it 

addresses; 

6 The human nose method involves the use of human operators to heat and then smell samples of pig fat to determine 

the presence of boar taint.  

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  Simplicity  –  the  material  provided  should  enable  the  end  user  to  understand  the 

practice without difficulty; 

  Sufficiency –  the material  should cover  all  the  important aspects and not assume 
much existing knowledge or cause users to have to look for clarification elsewhere; 

  Scope – the practices should be as widely applicable as possible; highly specific best 

practice material should be kept to a minimum; 

  Communicability – it should be transmittable and interpretable by the end users; 

  Amenability to improvement – it should be in such a format that it may be improved 
as  knowledge  or  techniques  evolve  without  the  need  for  a  full  redesign  of  the 
material. 

The  drafting  process  also involved  characterisation  of  advantages  and  disadvantages of 
each option. The approach taken to this characterisation was defined by the study team 
and  agreed  with  the  Commission.  Advantages  and  disadvantages  were  described  in 
qualitative terms. When quantitative information was available, this was also included in 
the  description.  Advantages  and  disadvantages  were  described  based  on  the  issues 
relevant  to  each  study  question  (for  a  description  of  each  question  see  Table 1).  These 
issues refer to: 

  Animal welfare – this includes animal discomfort and pain, and is principally relevant 

for Q2  

  Feasibility – this is applicable across most questions and includes consideration of: 

-  The resources required (cost, competence, time) 

-  The impact on the speed of process (particularly for slaughterhouses, under Q4) 

-  The  expected  percentage  of  entire  males’  carcasses  for  which  boar  taint  is 

detectable (Q4) 

-  The expected risk of price reduction for farmers in case of detectable boar taint 

carcasses (Q5) 

-  The percentage of detected boar taint meat compared to the quantity of meat 
they received, and the way such tainted meat can be used or marketed (Q6) 

  Impact on boar taint prevalence (for Q1 principally) 

  Reliability as a method to detect boar taint (for Q4) 

  Impact on market value of meat from uncastrated pigs (for Q7) 

  Impact on consumer acceptance (for Q8) 

  Ability to detect boar taint in products to be served or sold (for Q7 and Q8) 

3.2.3  Task 3.1 – Drafting of documents 

The process of drafting the documents was led by non-specialists. The lay writers used a 
common template that was designed by the project management team. 

The eight questions within scope were divided among the lay writers. The writers used the 
source material gathered during Task 2.  

After the completion of a first draft, the document was shared with a subject matter expert 
from the team. The work of the expert was guided by a checklist embedded into the draft. 
This identified the aspects to be addressed by the review of each section. 

The draft was then sent back to the lay writer for revision, and was once more reviewed 
by  the  subject  matter  expert.  Unless  further  edits  were  required,  the  draft  was  then 
reviewed by the project management team. The overall process is summarised in Table 4. 

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Table 4.  Process for drafting elements for best practices 

3.2.4  Task 3.2 – Preparation of draft illustrations 

Illustrations were used to communicate information about some practices. ICF’s illustrators 
were provided with a written request, supported by examples of the designs to be followed. 
The  style  of  the  illustrations  was  agreed  with  the  Commission.  We  adopted  the  style 
previously  used  by  ICF  for  the  DG  SANTE  project  “Preparation  of  best  practices  on  the 
protection of animals at the time of killing”, i.e. monochrome ink drawings of the subject 
matter. 

The illustrator provided sketches. These sketches were finalised in the style agreed, after 
completion of the consultation on the drafts elements. 

Images other than drawings were included in the drafts, an example being a flowchart that 
summarised the timeline for vaccinating pigs against boar taint.  

3.2.5  Task 3.3 – Interim report (updated Deliverable 1, Deliverables 2 and 3) and 

meeting 

The interim report provided updates to the inception report, the state of play (Deliverable 
2)  and  draft  elements  of  best  practice  addressing  each  of  the  eight  study  questions 
(Deliverable 3). 

Following  submission,  the  report  was  presented  at  a  meeting  held  at  the  Commission’s 
premises. A note summarising the points discussed and actions agreed at the meeting was 
produced and delivered to the Steering Group within 5 working days. Based on feedback 
received from the Commission, a revised final version of the interim report was submitted 
and then approved by the Commission. The Commission’s comments on the draft elements 
of  best  practices  were  not  addressed  in  the  interim  report  since  consultation  with 
stakeholders had already been initiated. These comments are addressed in this final report. 
Details  on  the  Commission’s  comments  and  on  how  these  have  been  addressed  are 
presented in Annex 5 alongside the comments received during the online consultation.   

3.3  Task 4: Consulting stakeholders on elements for best practices 

During Task 4, ICF consulted stakeholders on the draft elements of best practice, assessed 
feedback and contributions, and finalised the project outputs.  

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3.3.1  Purpose 

The consultation phase provided an assessment of the quality of the work undertaken in 
Task 3 and gathered comments that were used to inform improvements. It  was  also  an 
opportunity  to  clarify  the  purpose  of  the  project  with  stakeholders,  and  a  point  in  the 
process  where  stakeholders  could  express  any  concerns  they  may  have  about  the 
development of the best practice documents.  

3.3.2  Method 

The terms of reference required that the consultation include at least the following groups:  

  Stakeholders in some Member States; 

  EU stakeholders; 

  Member States' competent authorities;  

  Scientific institutes. 

The terms of  reference  emphasised  the need  to take into  account  the interests of small 
undertakings  active  in  local  markets.  Some  changes in  pig  production  methods  may  be 
perceived as unaffordable by small players in Europe’s pigmeat supply chains. 

In addition to the groups above, ICF also consulted with a number of selected:  

  Official veterinarians and veterinary practitioners;  

  NGOs; and 

  Thematic experts. 

ICF  consulted  stakeholders  via  an  interactive  web  platform  (section  3.3.3)  and  a 
stakeholder advisory board (section 3.3.6).  

3.3.3  Task 4.1 – Development of an interactive web platform 

The objective of this task was to create an online platform that could be used to gather 
stakeholder feedback on best practice elements. The platform enabled the review of draft 
documents  describing  best  practices.  It  was  designed  to  provide  secure  access  by 
consultees. It is an interactive tool to facilitate discussion on draft documents prepared by 
the  study  team.  During the  kick-off  meeting, it  was  decided that the platform  would  be 
hosted on ICF’s server. 

3.3.4  Task 4.2 – Launch and moderation of interactive web platform 

3.3.4.1  Stakeholder recruitment 

Email  invitations  for  participation  in  the  online  consultation  were  sent,  followed  by  two 
reminders over the consultation period. Emails included instructions for the access and use 
of the platform.  

The  online  platform  was  open  for  comments  for  8  weeks,  although  additional  time  was 
allowed  to  stakeholders  who  requested  so.  When  consultees  suggested  other  relevant 
contacts to consult, these were added to the platform. 

ICF organised and managed the consultation process. As discussed with the Commission 
at the kick-off meeting, the online platform was used to consult with those stakeholders 
who have been approached in previous phases of the work. 

3.3.4.2  Platform moderation 

ICF administered and moderated the online platform. Consultees were also able to provide 
information  privately rather  than through the  public  forum. Ultimately, many  consultees 
chose  to  send  feedback  via  email  rather  than  commenting  through  the  online  platform. 
Some comments were received on the platform but the forum was ultimately not used by 
stakeholders to discuss the relevant issues.  

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3.3.5  Task 4.3 – Analysis of responses 

The  project  team  analysed  and  verified  the  consistency  of  information  gathered  via  the 
online platform. The evaluation team carried out a rapid initial scan of comments and any 
additional documentation provided.  The purpose of this exercise was to establish: 

  Who contributed; 

  What  stakeholder  category/  country they  are  representing,  and  whether  they  are 

individual organisations or representative associations; 

  What aspects they addressed; 

  What their views and concerns are. 

A segmentation of the responses was carried out by: 

  Stakeholder group  

  Type of inputs provided by stakeholder: opinions, facts/ data, anecdotal evidence 

Feedback received through comments and emails was collated into separate tables for each 
of  the  eight  documents.  The  study  team  followed  up  with  stakeholders  to  confirm 
information  on  any  comments  that  were  unclear  or  to  gather  more  information  where 
comments  related  to  previously  unresearched  practices.  Once  comments  had  been 
reviewed,  ICF’s  response  to  each  comment  and  any  actions  taken  on  its  basis  were 
recorded in the table.  

When specific points called for expert evaluation and response, the project management 
team contacted the relevant experts within the project team and asked for a review of the 
comments and a reasoned response for use by the person in charge of revising the drafts. 

The table below indicated the number of stakeholder representatives invited to contribute 
through  the  online  platform,  and  the  number  of  stakeholder  representatives  who 
responded by submitting comments on the draft documents. Of those who responded, six 
submitted  comments  through  the  online  platform,  and  the  remaining  eight  submitted 
comments via email. The tables containing all comments received are available in Annex 
5.  

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Table 5.  Online platform - Number of stakeholders consulted by stakeholder type  

Stakeholder type 

Number of stakeholder 
representatives invited 

Number of stakeholder 
representatives who 
responded 

Animal welfare organisations 

Breeding companies 

Competent authorities 

Distributors 

Farmers 

Feed producers 

Processors 

Quality assurance companies 

Research institutes and 
experts 

Retailers and food service 
operators 

Slaughterhouses 

Slaughterhouses and 
processors 

Vaccine supplier 

Whole chain 

Total 

1 

3 

1 

1 

33 (7) 

6 

20 (11) 

6 (2) 

5 

17 (4) 

16 

5 (1) 

4 

2 (2) 

120 

1 

1 

1 

2 

1 

2 

3 

1 

1 

1 

1 

14 

Note: the numbers in brackets indicate how many, out of all stakeholders consulted, 
were representative associations 

3.3.6  Task 4.4 – Advisory board 

The draft documents were disseminated at two meetings of an advisory board. The purpose 
of  these  meetings  was:  to  promote  awareness  and  dissemination  of  the  study  results; 
gather  feedback  on  the  elements  for  best  practice;  and  support  their  take-up  among 
business operators. 

An important issue addressed with the advisory board was the feasibility of the 
best  practices  in  the  various  contexts  observed  in  the  EU.  A  substantial  share  of 
discussion time at these meetings was reserved for consideration of this issue. 

The two advisory board meetings were organised as follows: 

  One meeting was held after the draft elements of best practice had been completed 
(Task  3).  That  meeting  entailed  a  presentation  of  the  good  practice  documents, 
including the feedback received through the online consultation. Participants were 
invited  to  provide  their  feedback  and  thus  contribute  to  the  improvement  and 
validation of the content.  

  A second meeting was organised following the completion of the draft final report. 
In addition to providing an update on the revision of the elements for best practices, 
this  meeting  focused  on  the  challenges  associated  with  the  dissemination  and 
implementation of the good practices. It provided an opportunity to discuss the best 

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ways to further disseminate materials and achieve maximum impact, thus feeding 
insights into the second phase of the project.  

The  advisory  board  included  actors  with  extensive  practical  experience  of  the  topics 
covered in the study. 

Board  meetings  were  hosted  in  Brussels.  ICF  drafted  an  agenda  for  each  meeting.  The 
agenda included an introduction to the objectives of the study, an update of progress on 
data collection, and discussions on the different tools and solutions to market meat from 
uncastrated  or  immune-castrated  pigs.  All  prospective  participants  received  the  final 
agenda and an information pack with supporting documentation in advance of the meeting. 

The meetings were full day events to provide sufficient time for an in-depth discussion of 
the issues. They provided opportunities to present and discuss key challenges linked to the 
cessation of surgical castration and possible solutions. The meetings were attended by two 
senior representatives of the study team and one junior staff member. The meetings were 
conducted in English only. 

After the meetings, ICF sent notes of the discussion to all participants and the Commission. 
A  detailed note of how the  comments  received from  the  advisory  board  were taken  into 
account has also been provided to the Commission.  

The Advisory Board involved stakeholders from all stages of the supply chain and from all 
the countries involved in the data collection task. It also included representatives of animal 
welfare and research organisations. It included a mix of individual organisations, national-
level and EU-level associations.  

Table 6 presents the number of stakeholders who were contacted to be part of the Advisory 
Board, and the number of those who attended the first and second meetings.  

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Table 6.  First meeting of the Advisory Board - Number of stakeholders consulted by 

stakeholder type  

Stakeholder 
type 

Number of 
stakeholders 
contacted 

Breeders 

Farmers 

Feed producer 

Food processors 

Slaughterhouses 

Slaughterhouses 
and processors 

Veterinarians 

Vaccine suppliers 

Animal welfare 
organisations 

Quality assurance 
operators 

Retailers 

Research 
institutes and 
experts 

Grand Total 

1 

11 (10) 

1 

4 (2) 

8 (5) 

3 (1) 

1 (1) 

3 

1 

2 

4 (1) 

2 

41 

Number of 
stakeholders who 
attended the first 
meeting 

Number of 
stakeholders who 
attended the 
second meeting 

5 (5) 

3(3) 

1 (1) 

1 (1) 

1 (1) 

1 

1 

1 

1 

1 

13 

1 

1 (1) 

1(1) 

2 

1 

2 

11 

Note: the numbers in brackets indicate how many, out of all stakeholders consulted, 
were representative associations 

3.3.7  Task 4.5 – Finalisation of text and illustrations 

Feedback from consultations and advisory board meetings were used to review and finalise 
the elements of best practice, as presented in this final report. These reviews followed the 
same process as the development of draft practices. 

  The person who drafted the documents in Task 3 – a non-specialist with excellent 
drafting  skills  –  revised  and  finalised  the  drafts  based  on  the  set  of  responses 
provided to all the comments reviewed through the online platform; 

  The  illustrator  was  given  instructions  to  finalise  the  visuals  and  authorisation  to 

reproduce existing visuals was sought from the copyright holders; 

  Text  and  visuals  were  reviewed  by  the  project  management  team,  including  an 

English native speaker.  

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4 

Deliverable 1: Work plan 

A detailed schedule of deliverables is provided in Table 7. 

Table 7.  List of deliverables 

Deliverable 

Scheduled delivery date 

Kick off meeting and Inception Report – Deliverable 1 

6 April 2018 

Interim Report – Deliverables 1+2+3 

6 July 2018 

Draft Final Report – Deliverables 1+2+4 

8 October 2018 

Final Report 

9 November 2018 

A  Gantt  chart  is  provided  at  Table  8.  This  shows  the  phasing  of  tasks,  meetings  and 
deliverables.  

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Table 8.  Gantt chart phasing of tasks, meetings and deliverables 

Tasks

March

April

May

June

Month
July

August

September

October

November

Task 0 - Inception
Task 0.1: Mobilisation
Task 0.2: Kick-off meeting
Task 0.3:Team up
Task 1: Updated methodology and work plan 
Task 1.1: Scoping research
Task 1.2: Finalisation of the methodology
Task 1.3: Finalisation of work plan (timeframe)
Task 1.4: Finalisation of list of experts and organisations
Task 1.5: Inception report (D1) and meeting
Task 2: Collecting data and observation
Task 2.1: Desk research
Task 2.2: Contacts with Member State stakeholders
Task 2.3: Preliminary visits in Member States
Task 2.4: Comparative analysis, synthesis and identification of gaps
Deliverable 2 – State of play and identification of gaps
Task 3: Drafting of elements of best practices
Task 3.1 : Drafting of documents
Task 3.2: Elaboration of draft illustrations
Task 3.3: Interim report (updated D1, D2 and D3) and meeting
Task 4: Consulting stakeholders on elements for best practices
Task 4.1: Establish interactive web platform 
Task 4.2: Launch and moderation of web platform
Task 4.3: Analysis of responses
Task 4.4 – Finalization of text and illustrations
Task 4.5: Advisory board
Task 4.6 – Draft final report  (updated D1, D2 and D4) and meeting
Task 4.7 – Final report
    Meeting        Report    PR Monthly Progress Report

P R

P R

P R

P R

P R

P R

P R

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5 

Deliverable 2: State of play 

This section provides: 

  A  summary  of  the  options  identified  for  all  the  questions  listed  in  the  terms  of 

reference; 

  A  comparative  analysis  of  the  different options,  with  a  summary  of  the  evidence 

regarding advantages and disadvantages of each solution; and  

  An identification of gaps. 

It explains the practices currently used in different parts of the supply chain, i.e.: 

  Farming:  

-  Q1: Reducing boar taint through management techniques (such as feeding and 

breeding) 

-  Q2: Use of the vaccine against boar taint: this includes, the number of vaccine 
doses to be given to pigs, the time at which the vaccine is administered, and any 
recommendations for administration to pigs of different weights or ages 

-  Q3:  Ways  in  which  farmers  provide  assurance  to  slaughterhouses  that 

vaccinated pigs do not present detectable boar taint. 

  Slaughtering and processing: 

-  Q4: Detecting boar taint, quantifying and managing positive carcasses 
-  Q5:  Checks  and  initiatives  to  obtain  assurance  that  vaccinated  pigs  do  not 

contain detectable boar taint 

-  Q6: Dealing with meat with detectable boar taint 

  Retailing and food services: 

-  Q7: Increasing the market value of meat from uncastrated pigs, and preventing 

meat with detectable boar taint from reaching consumers 

-  Q8:  Increasing  consumer  acceptance  of  meat  from  vaccinated  pigs,  and 

preventing meat with detectable boar taint from reaching consumers   

The literature sources examined for the data collection task are listed in Annex 7. 

This document considers practices observable  at specific  points in the supply chain, and 
targeted at a specific type of actors within that chain. However, many of the challenges of 
switching  to  entire  males  or  vaccinated  pigs  relate  to  relationships  and  communication 
between  different members of  the  supply  chain.  In other  words, supply  chain  dynamics 
play  a  significant  role  in  hindering,  or  in  contributing  to  transitions  from  pig  meat 
production with surgical castration to pig meat production without surgical castration. 

For example, the costs and benefits of a transition to production without castration are not 
distributed equally between different participants in the supply chain. Switching to entire 
males means a different set of costs incurred by the farmer, the feed producer, and the 
slaughterhouse to achieve meat of quality and without boar taint. To incentivise change, 
these costs need to recognised across the chain. This can be done through slaughterhouses 
or end-buyers offering premiums to farmers to cover the additional costs of using specific 
breeds  of  animals  and  specific  feed  to  reduce  the  incidence  of  boar  taint.  The  retailer 
Delhaize in Belgium pays farmers participating in the ‘Beter voor iedereen’ label a €1 bonus 
per animal as well as compensation for additional feed costs. Often, however, the additional 
costs tend to be borne largely by the farmers themselves. Where supply chains are highly 
integrated, as is the case in one supply chain that has made the transition to entire males 
in France, this is less of an issue. However, where this is not the case, much depends on 
the relationship between slaughterhouses and farmers, which in many countries tends to 
be characterised by low trust.  

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A  bonus-malus  system7  related  directly  to  the  presence  or  absence  of  boar  taint  might 
incentivise  farmers  to  take  up  more  preventative  practices.  In  addition  to  incentivising 
farmers, this also reflects the economic loss incurred by the slaughterhouse as a result of 
the presence of detectable boar taint in a carcass. Such a penalty system linked to boar 
taint  detection  is  used  in  France.  Other  bonus-malus  systems  exist  where  penalties  are 
based on weight or are universal for all boars. The absence of more widespread boar taint-
based financial incentives is ascribed largely to the lack of objectivity of existing tests and 
the lack of trust between farmers and slaughterhouses. 

Ultimately, a transition to entire males or vaccinated pigs can only occur where there is an 
end market for entire males or vaccinated pigs: demand is the key driver for transition. 
For  most  supply  chains  in  Europe,  this  means  that  a  transition  can  only  occur  where 
retailers  are  willing  to  sell  such  meat.  Instances  where  a  transition  to  entire  males  or 
vaccinated pigs has been successful all involve cooperation between different actors in the 
supply chain, including:   

  Cooperation between retailers, breeding companies and farmers to develop and use 

low-taint breeds 

  Cooperation  between  retailers,  farmers,  processors  and  feeding  companies  to 
develop feeding solutions that address boar taint and other meat quality concerns; 
and  

  Cooperation  between  processors,  assurance  schemes  and  external  consultants to 

develop harmonised boar taint detection techniques. 

To the extent that these supply-chain level aspects have been documented in this study, 
they also appear in relevant sections of this report and in the elements of best practices. 
The rest of this section summarises the findings from the data collection phase. 

5.1  Practices at farm level 

Overall, the presence of non-castration and vaccination practices varied across countries. 
Uncastrated pigs are commercially produced in all the countries covered by this project, 
with the exception of Norway. In some countries (such as Spain and the UK), production 
of entire males is well-established.  

Vaccination  against  boar  taint  is  not  widely  practised  in  Europe,  meaning  that  the 
information received came from a small number of countries and sources. Belgium has the 
most  experience  with  vaccination.  Spain  and  the  Netherlands  also  reported  some  use. 
Norway had previously trialled the use of vaccination commercially, but it is no longer being 
used as frequently.  

A  wide  range  of  practices  was  found  at  farm  level  for  both  raising  entire  males  and  for 
dealing  with  vaccination.  Many  of  these  practices  were  also  already  documented  in  the 
literature. 

Several  feeding  solutions  were  identified,  and  a  number  of  them  are  commercially 
available.  Although  these  are  associated  with  raising  entire  males,  feeding  practices  to 
reduce taint could also be used for vaccinated pigs.  

There  are  additional  costs  associated  with  many  of  these  options,  however  both  entire 
males and vaccinated pigs have been shown to have more efficient feed conversion ratios 
than  surgically  castrated  males.  Previous  research8has  estimated  that  the  better  feed 
conversion can be valued at €7.11 per pig for entire males and €6.10 for vaccinated pigs. 

7 An incentive system that is designed to give positive reward for good performance, and impose a penalty for poor 

performance. 

8 Civic Consulting (2013). Study and economic analysis of the costs and benefits of ending surgical castration. Part 2 – 

Country studies. European Commission. Available at: 
https://ec.europa.eu/food/sites/food/files/animals/docs/aw_prac_farm_pigs_cast-alt_research_civic_pt2-country-
studies_20131202.pdf 

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The better feed conversion ratio has been cited as helping to convince many farmers in the 
Netherlands to switch to raising entire males when the market began to accept boar meat. 
In fact, so many farmers began to raise entire males that supply grew faster than demand 
and led to many challenges for the processing industry.   

The timing of slaughter appears to be used almost universally as a means of managing the 
risk  of  boar  taint,  based  on  either  weight  or  age,  although  the  exact  thresholds  vary 
depending on country and source.  

Recent research has looked at using breeding and genetics to reduce boar taint incidence. 
Breeding techniques have been found to be used at a commercial level in several countries.  

The practices identified for reducing boar taint through housing were all general practices 
associated with improved welfare. These practices are well documented, although it is not 
clear to what extent they impact boar taint prevalence.  

Although  vaccination  is  not  yet  widespread  in  Europe,  a  good  deal  of  information  was 
available  through  the  detailed  guidance  provided  by  vaccine  suppliers.  These  practices 
were  also  confirmed  by  farmers.  Similarly,  information  on  providing  assurance  that 
vaccination has worked was also provided by vaccine suppliers and confirmed by farmers.  

5.1.1  Q1  –  Techniques  and  best  practices  to  reduce  boar  taint  through 

management techniques (including feeding and breeding) 

5.1.1.1  State of the knowledge and comparative analysis 

Several  ways  to  reduce  boar  taint  at  farm  level  were  identified.  The  solutions  identified 
related to: 

  Management of boars; 

  Flooring, housing and pig management; 

  Selective breeding of pigs; 

  Feeding techniques; 

  Early detection of pigs which may be affected by boar taint; 

  Scheduling of slaughter; and  

  Transport to the slaughterhouse.  

Several  practices  were  identified  that  relate  to  the  management  of  boars.  These 
practices  are  intended  to  reduce  aggressive  and  sexual  behaviour.  Previous  guidance 
produced by Wageningen University9 has been referred to in the main text and many of 
the included practices are mentioned under flooring and housing or feeding.  

Many  of  the  practices  relating  to  flooring  and  housing  seek  to  improve  welfare  and 
thereby reduce stress. Reductions in stress are associated with less aggressive behaviour, 
fewer fights between animals and consequently a reduction in boar taint. Many of the better 
welfare  practices  identified  are  also  subject  to  EU  regulations  that  guarantee  minimum 
standards. These include keeping the density of animals low, controlling the temperature 
and providing enrichment. Keeping the density of animals low and keeping temperatures 
cool have been shown in the literature to be correlated with lower skatole levels10. 

9 Wageningen University. ‘Reducing mounting behaviour of boars – tips and recommendations’. Available at: 
https://www.boarsontheway.com/wp-content/uploads/2018/08/Flyer-Berengedrag-v4-engels-2.pdf  

10 Hansen, L., Larsen, A., Jensen, B., Hansen-Møller, J., & Barton-Gade, P. (1994). Influence of stocking rate and 

faeces deposition in the pen at different temperatures on skatole concentration (boar taint) in subcutaneous fat. 
Animal Science, 59(1), 99-110. 

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Partially or fully slatted floors are used in several countries (including Belgium, Denmark, 
France, Germany and the UK) to eliminate urine and faeces from the pens and keep them 
clean. Keeping pigs clean has been associated with reductions in boar taint11 and is used 
by most farmers. However, there are restrictions to the use of fully slatted floors in some 
Member States due to welfare concerns, as slatted floors can increase the risk of injury.  

A  variety of methods  are used for  grouping  pigs  to  reduce  stress.  Sex separation  was 
used in all countries to reduce aggression and, in some cases, to facilitate providing boars 
and gilts with different feed. However, farmers had mixed experiences with sex-separated 
rearing, with some indicating that it increased stress and led to higher levels of aggression 
among boars. As it appears to be common practice when raising boars, sex separation has 
been retained in the final documents but with a caveat added that indicates that on-farm 
experiences have varied. Sex separation is also considered to be vital for systems where 
pigs are raised to an older age/higher weight, as not separating larger/older pigs by sex 
can lead to a risk of sow pregnancy. Wean-to-finish grouping, where pigs are kept with 
their  litter  mates  until  slaughter,  was  also  identified  as  a  commercially-used  practice  to 
reduce  stress.  One  example  was  given  from  the  Netherlands  of  the  two  practices  being 
used together: pigs being separated by sex but kept with their same-sex litter mates with 
little to no mixing after weaning.    

Wet feeding is a technique used frequently in the industry and was reported in the UK, 
Denmark and Germany. It involves feeding pigs dry feed mixed with water, so that pigs 
drink  their  feed  rather  than  chew  it.  Wet  feeding  is  not  explicitly  done  to  reduce  the 
instance  of  boar  taint,  but  instead  to  improve  the  ability  to  control  feed  conversion  per 
pen. It is seen as a way to reduce competition between pigs while feeding, which reduces 
aggression  and  could contribute to reducing the  instance  of  boar taint. Wet  feeding has 
been demonstrated in the literature to contribute to a reduction in skatole levels12.  Wet 
feeding, along with other practices to reduce competition at feeding have been included 
alongside other flooring and housing practices, rather than with other feeding practices, as 
they require significant changes to infrastructure.    

Pietrain and Duroc breeds are used in some countries and these are considered to be at 
lower risk for boar taint. This has been tested and confirmed by several studies13. Several 
breeding companies have begun to include boar taint as a factor in their selection methods, 
in some instances in cooperation with retailers or processors. Topigs Norsvin has succeeded 
in reducing boar taint instance across their various lines (Talent, Tempo and Top Pi) and 

11 Aluwé et al. (2011a). Influence of soiling on boar taint in boars. Meat Science, 87:3, pp. 175-179. Available: 

https://pure.ilvo.be/portal/en/publications/influence-of-soiling-on-boar-taint-in-boars(c52065ec-c378-45d2-a37f-
52c10eaae493).html  

12 Andersson et al. (1997). The effects of feeding system, lysine level and gilt contact on performance, skatole levels 

and economy of entire male pigs. Live Prod Sci, 51:1-3, pp. 131–40.  

Allen et al. (1997). Effect of nutrition and management on the incidence of boar taint. In: Boar taint in entire male 
pigs. Proceedings of a meeting of the EAAP working group "Production and Utilisation of Meat from Entire Male 
Pigs"; 1997 Okt 1-3; Stockholm, Sweden. Wageningen, the Netherlands: Wageningen Pers; 1997. p.88–91. 

Kjeldsen, N. (1993). Practical experience with production and slaughter of entire male pigs. In Measurement and 

prevention of boar taint in entire male pigs, Roskilde, Denmark, 1992, (ed. Bonneau, M.), Institut National de la 
Recherche Agronomique, les colloques no. 60, pp. 137–144 

13 Xue et al. (1996). Breed differences in boar taint: relationship between tissue levels of boar taint compounds and 

sensory analysis of taint. Journal of Animal Science, 74. pp. 2170-2177. Available: 
https://www.researchgate.net/publication/14327322_Breed_Differences_in_Boar_Taint_Relationship_between_Tis
sue_Levels_of_Boar_Taint_Compounds_and_Sensory_Analysis_of_Taint  

Aluwé et al. (2011b). Influence of breed and slaughter weight on boar taint prevalence in entire male pigs. Animal, 

5:8, pp. 1283-1289. Available: https://www.cambridge.org/core/journals/animal/article/influence-of-breed-and-
slaughter-weight-on-boar-taint-prevalence-in-entire-male-pigs/139CA9B5D3C4A6D2477C0E3D5065DF8F 

Institute of Agriculture and Food Research and Technology (2015). Study on how to achieve reduction of boar taint 

compounds by breeding, feeding and management techniques. European Commission. Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/aw_prac_farm_pigs_cast-alt_research_irta_20150216.pdf 

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has a special line, Nador, with an even smaller chance of boar taint. Nador sperm can be 
purchased at a premium of €1 per dose. Figure 2 shows the trend in reduced boar taint 
prevalence achieved for the Top Pi, Talent and Tempo terminal boar lines of Topigs. 

Figure 2.  Topigs’ results in reducing boar taint prevalence through breeding14 

In  France,  the  breeding  company  Nucleus  (of  which  the  retailer  Cooperl  is  the  major 
shareholder) has worked to develop a line of low-taint Piétrain pigs, known as INO (from 
the French “inodore”, without odour) pigs, for use in Cooperl’s entire male supply chain. 
The INO sperm is available commercially and there is no premium charged as compared 
to other  lines.   In  Belgium,  Delhaize has  worked  with  breeding  company  PIC  to  develop 
low-taint sperm for use in products with a castration-free pork label.15 PIC has indicated, 
however, that  there  have  been  some issues  with  pigs  bred  for low taint.  Pigs  bred  with 
low-taint  sperm  have  bellies  of  reduced  size  and  quality  and  low-taint  sperm  may 
negatively impact sow productivity16. 

Additionally,  recent  work  has  been  done  through  a  project  at  the  University  of  Bonn  in 
Germany,  where  genetic  research  helped  lead  to  the  offering  of  low-taint  sperm.  This 
sperm is commercially available at a premium through GFS in Germany, who are marketing 
the  sperm  under  the  name  Inodurus  2.0.  The  German  slaughterhouse  Westfleisch  has 
stated  their  intention  to  ask  their  contract  suppliers  to  use  Inodurus  2.0  sperm  when 
finishing boars17.   

Although  the  use  of  feed  additives  to  reduce  boar  taint  has  been  discussed  in  the 
literature  and  many  examples  described,  few  have  been  used  in  commercial  practice. 
Changes to feed can impact the production of skatole, one of the main chemical compounds 

14 Topigs Norsvin (2018). Less boar taint with breeding. Available at: https://topigsnorsvin.com/news/less-boar-taint-

breeding/   

15 Ordelman, E. (2018) Belgian retailer launches castration-free pork label. Pig Progress. Available at: 

https://www.pigprogress.net/Piglets/Articles/2018/6/Belgian-retailer-launches-castration-free-pork-label-
298440E/  

16 Knudsen, N. (2018) Neal Matthews, PIC: "Achieving that perfect piece of pork". Available at: 

https://www.pigprogress.net/Finishers/Articles/2018/11/Marbling-has-been-overrated-in-pork-
352450E/?cmpid=NLC|pigprogress_focus|2018-11-09|Neal_Matthews,_PIC:_  

17 van Dooren, Kees (2018) Ki-organisatie GFS introduceert stankvrije eindbeer. Boerderij. Available at: 

https://www.boerderij.nl/Varkenshouderij/Nieuws/2018/11/Ki-organisatie-GFS-introduceert-stankvrije-eindbeer-
357289E/  

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responsible for boar taint18. Chicory root (inulin) has been used commercially by at least 
one producer in the Netherlands, but has been cited as being too expensive generally for 
commercial  use.  Chicory  root  (either  whole,  dried  or  as  an  extract)  has  been  shown  to 
reduce boar taint in several studies19. A recent study has also indicated that chicory root 
only needs to be provided to boars three to four days prior to slaughter (rather than two 
weeks  prior  to  slaughter).20  This  significantly  reduces  the  costs  of  using  this  practice 
commercially.  One  commercially-available  feed,  Taintstop  (produced  by  Dumoulin), 
combines several different ingredients intended to address boar taint and was being tested 
by  some  of  the  farmers  contacted  in  Belgium.  It  was  also  mentioned  by  farmers  in 
Germany,  however  none  were  currently  using  it  due  to  the  higher  cost.  An  experiment 
comparing Taintstop feed to a control found that it contributed to a significant reduction of 
tainted samples21. A second commercial feed solution produced by the Dutch feed company 
Vitelia has been trialled, and has recently become commercially available.  

For  farmers  considering  the  cost  of  feed  additives,  it  is  relevant  that  evidence  from  the 
literature shows that boars have a more efficient feed conversion ration as compared to 
surgically castrated males: around 0.28 kg less of feed is required to produce 1 kg of pig 
meat when raising boars22. 

Using a cereal-only or low-protein diet in the days leading up to slaughter was mentioned 
by a few sources as a practice which might contribute to a reduction in skatole content. 
However, there were divergent opinions on this practice, possibly because it was confused 
with the  protein  content of  the  diet.  Increasing  the  protein content in  diets  intended  for 
boars contributes to a higher growth rate, meaning that animals can be slaughtered at a 
younger age. Low-protein diets have been associated in the literature with higher instance 
of  boar  taint23  and  evidence  suggests  that  results  are  dependent  on  the  type  of 
carbohydrate and protein24. There was evidence of reducing protein content or providing a 
grain-based diet three to four days prior to slaughter being used commercially, and it was 
considered a cost-effective practice. 

18 Jensen, B.B. (2006) Prevention of boar taint in pig production. Factors affecting the level of skatole. Acta Veterinaria 

Scandinavica 48(1): S6. 

19 Hansen, L., Mejer, H., Thamsborg, S., Byrne, D., Roepstorff, A., Karlsson, A. Tuomola, M. (2006). Influence of 

chicory roots (Cichorium intybus L) on boar taint in entire male and female pigs. Animal Science, 82(3), 359-368. 

Byrne, D.V., Thamsborg, S.M. and Hansen, L.L. (2008). A sensory description of boar taint and the effects of crude and 
dried chicory roots (Cichorium intybus L.) and inulin feeding in male and female pork. Meat Science, 79(2), 252-
269. 

Zammerini, D., Wood, J.D., Whittington, F.M., Nute, G.R., Hughes, S.I., Hazzledine, M. and Matthews, K. (2012). Effect 

of dietary chicory on boar taint. Meat Science, 91(4), 396-401. 

20 Maribo, H., Jensen, B.B. and Thoning, H. (2015) Fibre reducerer skatol I hangrise. Meddelelse Nr. 1055. Available at: 

https://svineproduktion.dk/publikationer/kilder/lu_medd/2015/1055  

21 Boulet et al. (2017). Influence of TAINTSTOP, an innovative feed concept on boar taint. BAMST. Available: 
http://www.ca-ipema.eu/download/289/documents/oieras/orals_oeiras/2_N_3_Guy_Janssens.pdf  

22 Civic Consulting (2013). Study and economic analysis of the costs and benefits of ending surgical castration. Part 2 – 

Country studies. European Commission. Available at: 
https://ec.europa.eu/food/sites/food/files/animals/docs/aw_prac_farm_pigs_cast-alt_research_civic_pt2-country-
studies_20131202.pdf 

23 Nold, R.A., Romans, J.R., Costello, W.J., Henson, J.A. and Libal, G.W. (1997). Sensory characteristics and carcass 
traits of boars, barrows, and gilts fed high- or adequate-protein diets and slaughtered at 100 or 110 kilograms. 
Journal of Animal Science 75(10): 2641–2651. 

Lundström, K., Malmfors, B., Stern, S., Rydhmer, L., Eliasson-Selling, L., Mortensen, A.B. and Mortensen, H.P. (1994). 

Skatole levels in pigs selected for high lean tissue growth rate on different dietary protein levels. Livestock 
Production Science 38(2): 125-132. 

24 Jensen, B.B. (2006). Prevention of boar taint in pig production. Factors affecting the level of skatole. Acta Veterinaria 

Scandinavica 48(1): S6. 

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In  addition  to  feeding  higher  protein  diets  at  certain  phases,  adjusting  the  amino  acid 
balance  in  boar  feed  was  identified  as  another  feasible  practice  for  encouraging  faster 
growth in boars, so that they are younger at slaughter. 

Fasting prior to slaughter was identified as being used in Denmark, Germany and the UK 
but no association was made with how this might impact boar taint. Comments received 
during  the  advisory  board  meeting  suggested  that  fasting  prior  to  slaughter  may  help 
improve cleanliness during transport, which could help to reduce taint. This practice was 
not ultimately included as a separate best practice, but has been mentioned as a ‘thing to 
consider’ as an aspect of transport.  

Organic acid feed additives were used in Denmark and Germany, but this was explicitly for 
the reduction of salmonella and no connection was made to boar taint.  

A  number  of  additives  that  were  identified  in  the  literature  were  not  being  used 
commercially  by  any  of  the  farmers  interviewed.  These  include:  potato  starch,  tannin 
extract, pueraria lobate (kudzu root), non-nutritive adsorptive materials (active C, zeolite), 
rye,  additional  dietary  fibres,  readily  fermentable  carbohydrates,  sugar  beet,  lupine, 
jerusalem artichoke, coconut palm cake and yucca extract. Although we found no evidence 
of commercial use, feeding rye to pigs has been subjected to a large and successful trial 
by farmers in Germany and may be a future option for low-taint feeding25. 

Farmers in Spain, the Netherlands and the UK indicated that pigs were checked regularly 
for signs of aggression and that it was possible to separate particularly aggressive pigs or 
mark them for slaughter at an earlier age. This was cited as being a difficult practice to 
implement  by  one  farmer  in  Belgium,  however,  due  to  the  constant  state  of  agitation 
among  pigs  in  pens.  Additionally,  this  was  felt  to  be  a  difficult  and  largely  ineffective 
practice to enact for entire males by stakeholders during the consultation. As such, it was 
not included in the final text.  

Slaughtering at a younger age or weight than would be done for other pig types is done 
for  entire  males  across  all  farms.  Age  is  generally  considered  to  be  a  more  effective 
measure of boar taint risk than weight, but weight cut-offs appear to be common industry 
practice. Most farmers seem to use weight as the defining metric, although the maximum 
weight for  boars varies  between  countries.  Maximum  weights  mentioned include  105  kg 
(Spain), 110 kg (the Netherlands and the UK) and 115 kg (Denmark and Belgium). One 
producer in the UK mentioned slaughtering by a specific age (25 weeks) and a few farmers 
mentioned sending particularly aggressive pigs to slaughter at a younger age. There are 
currently trials  underway in  the  UK using  boar taint  detection to  determine  whether the 
current standard cut-off weight for boars could be raised. Using weight cut-offs to reduce 
boar taint risk was cited as problematic be some stakeholders, as it does not account for 
pigs that  are ‘slow growers’  and may end up much older at slaughter and with a higher 
risk of boar taint because of this.   

Farmers  in  the  UK  and  the  Netherlands  also  identified  transporting  pigs  to  the 
slaughterhouse in split sex groups as a potential best practice. This was also identified by 
slaughterhouses as a best practice; receiving pigs in split sex groups can help reduce stress 
and can facilitate the logistics of processing boars and detecting boar taint.  

5.1.1.2  Data gaps 

Many options for feed were identified as being uneconomic, but little information was 
available  on  actual  costs.  A  commercial  feeding  solution,  developed  specifically  to 
reduce boar taint, was identified as costing around €100 per tonne more than normal feed, 
but this figure was from Belgium and it is not clear whether this applies to other countries.  

25 Ter Beek, V. (2018) Rye: Influence on Salmonella and boar taint in finishers. Pig Progress. Available at: 

https://www.pigprogress.net/Finishers/Articles/2018/2/Rye-Influence-on-Salmonella-and-boar-taint-in-finishers-
245681E/  

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Although wet feeding is purported to help with the reduction of boar taint, as it is not used 
explicitly  for  this  purpose  its  relationship  to  boar  taint  reduction  is  difficult  to 
quantify. There was also no information available on the costs of this system and how the 
benefits of better feed conversion might reduce overall costs in the long term.   

The  relationship  to  boar  taint  is  even  more  tenuous  for  other  feeding  practices  used 
commercially, such as fasting and the use of organic acids in feed. For this reason, these 
are not included in the final elements of best practice.  

There  is  little  empirical  research  indicating  any  measurable  impact  from  better 
welfare and stress reduction practices on boar taint.  Keeping  pigs  clean  has  been 
shown in the literature to be likely to have an effect, but the impacts of other practices do 
not  appear  to  have  been  tested.  However,  there  appears  to  be  agreement  among 
stakeholders  that  these  practices  have  a  positive  impact  on  boar  taint  reduction  and 
improve welfare overall. 

Although behavioural indicators are used by some farmers to single out aggressive pigs, 
as with better welfare practices, there is limited evidence available as to how this directly 
relates to  boar taint  prevalence.  No  other on-farm  assessments for boar taint  risk  were 
identified.  

Avoiding split marketing (or ensuring that pigs in the same group are sent to slaughter 
at the same time) is considered better for welfare but no farmers confirmed that they use 
this  practice. Even though  pigs  are usually  kept  with  group mates,  pigs  may  be sent to 
slaughter  at  different  times  due  to  differences  in  growth  rates  and  in  some  instances, 
problematic behaviour.  

Slaughtering pigs at a lower weight will generally lead to a lower price per carcass. It is 
not  clear  how  much  lower  this  price  will  be,  and  how  significant  this  difference  is  for 
different  cut-off  points.  For  example,  a  generally  applicable  estimate  of  the  economic 
impact of slaughtering at 105 kg versus 115 kg has not been found, and it is not clear how 
significant  the  difference  in  risk  of  boar  taint  is  between  these  weights.  These  cut-off 
weights may also differ between breeds, but no specific information on this was available. 

Keeping  pigs  clean  and  comfortable  during  transport  is  important  for  welfare, 
although it is not clear whether this can also help reduce boar taint26. Transportation issues 
therefore have not been included in the best practices for this report. 

Case study: COOPERL’s transition to entire males 

COOPERL is a large pig meat producer in France that integrates farmers, feed producers, 
slaughterhouses and processors. In 2013 COOPERL transitioned towards the production of 
entire males. 

This transition was driven by COOPERL’s earlier commitment to animal welfare. COOPERL 
was inspired by the example of other producers in Germany and the Netherlands having 
transitioned to producing meat from entire males. Several visits in those countries in 2010 
helped COOPERL collect additional information and devise a plan for testing the feasibility 
of such a transition at COOPERL. 

A first trial was run, whereby volunteer farmers were asked to stop surgical castration but 
not change any of their other practices. In that phase, COOPERL applied the human nose 
method for detecting boar taint, based on Dutch protocols. Following an evaluation of the 
trial, a second phase of optimisation took place.  

The evaluation of the trial involved a review of all the additional savings and costs that the 
transition  to  entire  male  production  entailed  for  farmers,  feed  producers,  and 

26 The following source provides detailed guidance on transporting pigs: Consortium of the Animal Transport Guides 

Project (2017-rev1). Revision May 2018 ‘Guide to good practices for the transport of pigs’ Available at:  
http://animaltransportguides.eu/wp-content/uploads/2016/05/D3-Pigs-Revised-Final.pdf  

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slaughterhouses  at  COOPERL.  This  evaluation  broadly  concluded  that,  while  the  feed 
producer was negatively impacted because of the better feed conversion of entire males 
and therefore reduced  quantities of feed  required,  the  farmer  benefited  greatly:  besides 
doing away with the effort of surgically castrating the pigs and the costs of accompanying 
health checks / treatments, farmers who produce entire males have also fewer dejections 
and  therefore  can  more  easily  manage  the  environmental  impact  of  their  operations. 
Finally,  slaughterhouses  incur  the  additional  costs  of  boar  taint  detection.  The  overall 
evaluation  of  those  costs  and  benefits  showed  that  the  transition  would  generate  a  net 
benefit to COOPERL. 

The transition from trial to commercial production  took place  in 2013. This included  the 
establishment of a penalty system for carcasses with detectable boar taint, linked to the 
human nose tests carried out on each individual carcass at the slaughterhouse, and to a 
systematic  feedback  to  the  farmer  on  the  level  of  boar  taint  detected  in  each  batch. 
COOPERL has also provided reports to farmers each trimester that enables each farmer to 
compare its performance relative to its peers. 

At  around  that  time  COOPERL  also  invested  in  research  in  genetics  through  its  parent 
company  NUCLEUS.  Specifically,  research  was  conducted  by  NUCLEUS  jointly  with  the 
French Institute for Agronomical Research (INRA) to develop a method for qualifying boars 
in terms of the inheritable risks of boar taint, working with the Pietrain breed. This has led 
to individual testing of all Pietrain boars provided by NUCLEUS, and to the elimination of 
those detected as presenting a high risk of boar taint. As a result, NUCLEUS has developed 
a  label  “INO”  (which  stands  for  the  French  inodore,  “without  smell”)  for  these  Pietrain 
boars.  

COOPERL’s  transition  to  the  production  of  entire  males  was  not  driven  by  demand  by 
retailers and other buyers, nor by animal welfare organisations. To reassure retailers and 
Business-to-Business (B2B) buyers that the transition was beneficial to them and did not 
present risks, COOPERL ran trials with both. For example, COOPERL ran trials with store 
managers,  whereby they  were  informed in  advance  that,  for  a  given  period,  they  would 
only receive meat from entire males. There would be close interaction between a COOPERL 
representative and the store manager during that trial, to monitor any variations in sales 
and  any  consumer  complaints.  COOPERL  also organised numerous  visits  for  retailer  and 
B2B representatives to inspect the full process, and especially the human nose method, to 
convince  them  of  its  reliability  for  detecting  boar  tainted  carcasses.  The  human  nose 
method at COOPERL has also been audited and certified annually by the German company 
SGS,  which  provides  additional  reassurance  to  the  rest  of  the  supply  chain.  COOPERL 
highlighted for its B2B clients that carcasses of entire males are easier to process than that 
of castrated males, which means an economic benefit for them as well. 

While these efforts have proved successful in most cases, and COOPERL has managed to 
take retailer and B2B clients onboard so that it successfully provides entire male meat to 
an estimated 13 millions consumers per year, obstacles remain, including by clients that 
sell premium, labelled products. 

5.1.2  Q2 – Techniques and best practices to vaccinate pigs  

5.1.2.1  State of the knowledge and comparative analysis 

Information  on  the  use  of  vaccination  was  mainly  supplied  by  farmers,  vaccine 
manufacturers, and slaughterhouses27. Supporting information was also extracted from the 
websites of vaccine suppliers, and from training materials for farmers.  

Practices were identified in the following main areas:  

27 In Norway, the immunocastration vaccine is administered by slaughterhouses, while in other countries this is done 

by farmers or staff contracted by vaccine suppliers. 

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  The  overall  vaccination  process,  and  more  specific  details  of  when  and  how  the 

vaccine against boar taint should be administered; 

  The administration of an additional dose of vaccine to larger pigs.  

  Feeding of vaccinated pigs; and  

  Vaccination tools. 

Some  of  the  quantitative  information  provided  on  the  vaccination  process  referred  to 
practices applied in third countries that have more experience of using the vaccine against 
boar taint (such as Brazil)28. These practices were included in the final elements of best 
practice  when  considered  applicable  to  the  EU  context  (based  on  feedback  from 
stakeholders and our team of experts). 

One dose of Improvac costs farmers between €1.40 and €1.50. If farmers vaccinate twice, 
this  means  that  the  total  cost  per  pig  will  be  between  €2.80  and  €3.00.  This  cost 
information was confirmed by the vaccine producer.  

Farmers  tend  to  follow  the  manufacturer’s  instructions  about  the  vaccination  process, 
including the timing for administering the doses. The first dose is administered in pigs 
older than  eight  weeks,  and  there  is  a  four-week  interval  between  the  first  and  second 
doses. The farmers consulted also tended to apply a similar delay between the second dose 
and slaughter (i.e., four to six weeks), in line with the manufacturers’ recommendations. 
There are documented cases of both early29 and late vaccination30 of pigs.  

The  administration  of  three  doses  to  larger  pigs  and  special  feeding  practices  for 
vaccinated pigs were reported in Spain. The administration of four doses was documented 
in Italy for the production of large pigs destined for organic Parma ham only. In the latter 
case, the producer noted the difficulty of applying that many doses on a single animal, and 
the  challenges  of  achieving  a  product  that  satisfied  local  certification  standards.  While 
Improvac was considered economically profitable in other markets, that was not the case 
there. 

The  stakeholders  consulted  appeared  to  use  the  same  tools  (i.e.,  a  dosing  gun  –  see 
section 9) to administer the vaccine. 

The following additional methods cited in the literature were not reported as being used in 
commercial settings: 

  The  practice  of  administering  the  first  vaccine  dose  to  pigs  younger  than  eight 

weeks.  

  The  use  of  special  equipment  for  large-scale  vaccination.  The  stakeholder 
consultation suggested that, both in small and large farms, animals are vaccinated 
one by one. None of the stakeholders  consulted used special  equipment  for mass 
vaccination.  

  Special  restraining  methods  for  larger  pigs:  according  to  consultees,  both  piglets 
and  adult  pigs  could  be  vaccinated  in  their  pens,  and  do  not  require  individual 
restraining.  

28 Specifically, the consideration that, when farms are well experienced with the use of the vaccine, the proportion of 

pigs requiring a third dose may be as low as 0.3% of pigs. 

29 i.e., the first dose of the immunocastration vaccine is administered as soon as possible, once the pig has reached 

eight weeks of age. 

30 i.e., the first dose is administered as late as possible, considering the expected age of slaughter. 

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Case study: Vaccination protocol to produce cured hams in Spain 

In  Spain,  farmers  vaccinate  Iberian  pigs  against  boar  taint  to  produce  cured  hams. 
Vaccination  has  been  successful  in  improving  profitability  and  animal  welfare  while 
maintaining high product quality.  

The vaccine is administered as follows: 

Two-doses protocol for pigs reared in intensive systems: the vaccine is administered 
at 26 and 30 weeks of age for pigs aimed for slaughter at 40 weeks. 

Three-doses  protocol  for  pigs  reared  in  extensive  systems:  the  three  doses  are 
administered respectively at 30, 34 and 44 weeks of age, with a slaughtering age of 52 
weeks.  

When applied correctly, these protocols ensure high levels of meat quality. Trials carried 
out in Spanish slaughterhouses and cutting plants since 2010 demonstrate that cured meat 
from vaccinated pigs is similar to that  from physically castrated  pigs in  terms of colour, 
percentage of marbling, and water-holding capacity.  

Several benefits from vaccination are reported. Aggressiveness is reduced, and this helps 
avoiding pigs getting injured. After the second dose, pigs become more feed-efficient and 
reach a higher weight at the time of slaughter, which result in increased profitability for 
the farmer. The feed conversion ratio of vaccinated pigs is close to 3% lower than castrated 
males.  Feed  expenses,  which  are  a  key  component  of  pig  farmers’  costs,  are  therefore 
reduced31.  

The transition from physical castration to vaccination did not require any changes in farms’ 
existing infrastructures, management systems, or vaccination guidelines. The main change 
relates  to  the  adaptation of  pigs’  diet  after  the administration  of the second  dose.  A  pig 
expert reported this is key to achieving profitability and high quality of cured products.  

Prior to the second dose, vaccinated pigs are fed the same diet as entire pigs. After the 
second dose, pigs behave as physically castrates: on a daily basis, they voluntarily tend to 
eat up to 20% more feed than before the second administration of Improvac.  

The  diet  is therefore modified. For  pigs  reared in intensive systems, the  diet is  adapted 
from weeks 30-32 of age. The ratio between energy and amino acids is adjusted, and the 
proportion of amino acids is reduced by decreasing all individual amino acids equally. The 
proportion of energy coming from carbohydrate is increased compared to energy from fat. 
Furthermore, more fibre and more trace elements are provided. Provision of E Vitamin is 
increased  to  improve  meat  quality.  Other  vitamins  and  minerals  are  kept  within  legal 
standards. 

Case study: vaccination protocol applied by a Polish farm 

The  following  case  study  presents  the  experience  of  a  Polish  producer  with  vaccination 
against boar taint. The producer has two breeding farms with a stock of about 7000 sows 
and four fattening farms. They produce around 180 thousand piglets per year. Of these, 
around 35000 will go to external farms for fattening. The rest will be fattened in their own 
farms. The following is a transcript from an interview with Zoetis conducted in 2014. 

“We have started to test Improvac in 2009 on a group of 1100 boars. Starting end of 2010, 
we have begun to routinely use the Improvac vaccination technology. Our decision to start 
with Improvac was made based on several arguments. A first reason was to be prepared 
for  restrictions  around  piglet  castration  in  the  future.  The  second  reason  was  a  purely 

31 Palomo Yagüe, A. (2012). Inmunocastración en machos: resultados en cerdos ibéricos. Available at: 

https://www.3tres3iberico.com/articulos/inmunocastracion-en-machos-resultados-en-cerdos-ibericos_817/  

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economic. We think of vaccination as an investment in the production process. The benefits 
from using Improvac are in a lower consumption of feed, better growth and better meat 
quality.  

Ultimately, we are a large and modern company and we are always looking for innovative 
solutions that can bring sustainable and economic benefits. 

In  our  farms,  we use  Improvac  in  a  slightly  different  way  from the recommendations of 
the  manufacturer.  We  extend  the  time  to  slaughter  to  8-9  weeks  after  the  second 
vaccination.  The  results  of  our  own  tests  and  our  experience  over  many  months  have 
shown  that  this  is  giving  us  the  best  results.  We  have  seen  that  after  the  second 
vaccination,  the  animals  start  to  grow  very  fast  with  high  levels  of  daily  gain.  For  our 
production, this 8-9 week period is optimal. It maximizes our economic return and it is still 
completely  safe  in  terms  of  boar  taint.  In  our  slaughterhouse,  we  don’t  experience  any 
significant levels of pigs with taint after vaccination. We have introduced a control program 
that  consists  of  close  observation  of  the  pigs  two  weeks  after  the  second  vaccination  is 
given. One month before slaughter (4 weeks) a final compliance monitoring is performed. 
If  we  see  any  mating  behaviour  in  any  of  the  boars,  we  still  have  sufficient  time  to 
revaccinate these animals a third time. These are sporadic cases, but they do happen. The 
test is then completed by filling a report that is signed by the farm manager and by the 
veterinarian.  

We  are  in  a  privileged  position  as  almost  100%  of  our  animals  are  sent  to  our  own 
slaughterhouse.  Thus,  in  the  beginning  it  was  easier  to  convince  the  slaughterhouse 
management. Of course, during the first deliveries, there was inevitable excitement over 
this  new  type  of  pigs  at  the  line.  Inspecting  veterinarians  examined  and  evaluated  the 
carcases with much greater commitment. Close inspection of testicles and tests including 
the  cooking  and  frying  of  meat  to  evaluate  the  presence  of  boar  taint  were  performed. 
After a while, everything returned to normal. In a period in which 140,000 boars were sent 
to the slaughter, the inspectors detected less than 30 boars suspected of having boar taint. 

The inspectors continue to monitor the situation, but we see no significant [problems].  

Our plan is to continue using Improvac for vaccinating our boars. We don’t currently see 
any other alternatives, so we are not presently looking for other solutions. 

I  would  say,  do not  be  afraid.  Try  for  yourself.  If  the  product is  given  at the  right  time 
intervals, then it is, on one hand very safe with regards to meat quality, and on the other 
hand it  gives  an opportunity to improve  the  economics  of  the  production,  which is  very 
important. Every few  extra  zlotys  earned  per  pig  are  at least  a  good  reason to  give the 
product a try.”    

5.1.2.2  Data gaps 

There  were  few  information  gaps  on  the  use  of  the  vaccine  against  boar  taint.  Vaccine 
suppliers  provided detailed information from  training that  is  delivered in EU  and in third 
countries.  It  was  possible  to  confirm this information  with  the  farmers  and  experts that 
were consulted. 

However,  it  was  difficult  to  identify  quantitative  information  on  feeding  practices 
(such  as  feedings  costs)  that  could  be  considered  representative  of  various  production 
systems. This is due to the significant variability in standard slaughtering weights from one 
country to the next, which result from commercial considerations.   

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5.1.3  Q3  –  Techniques  and  best  practices 

to 
slaughterhouses that vaccinated pigs do not present detectable boar taint 

to  provide  assurance 

5.1.3.1  State of the knowledge and comparative analysis 

To provide assurance to slaughterhouses that vaccination has been performed correctly, 
farmers  in  Spain  and  Belgium  perform  on-farm  controls  prior  to  sending  pigs  to  the 
slaughterhouse. For assurance purposes, farmers in Spain and Norway also keep records 
of the vaccination process and supply these documents to slaughterhouses. None of these 
practices were reported by Dutch farmers. 

On-farm  checks  performed  both  in  Spain  and  Belgium  include  the  observation  of  pigs’ 
behaviour, which is considered a reliable tool by many stakeholders. Measuring testes was 
used to select at-risk pigs by some, and appears to be common practice in Brazil, but was 
found to be a difficult and inconclusive practice by many stakeholders. Studies have also 
indicated that testes size is an unreliable indicator of the success of the vaccine.32 As such, 
it has not been included in the final version of the best practices. The literature reviewed 
for  this  project  also  referred  to  the  use  of  physiological  indicators33  to  verify  that 
vaccination  has  been  successful;  however,  the  data  collection  did  not  find  any  of  these 
indicators being used in commercial settings.  

Spanish farmers supply paper-based documentation to slaughterhouses. This typically 
includes details such as the numbers of vaccinated pigs, the dates of vaccination, and the 
on-farm checks performed to assess the result of the vaccination. Vaccination details will 
also be included as part of general medical records in many countries. In third countries 
(such  as  Brazil),  farmers  use  electronic  systems  to  transmit  this  documentation.  These 
systems have been reported within the final documents on best practices, as they may be 
also applicable to EU farmers. 

Previous  research34estimated that the  costs  of  detection  for vaccinated  pigs was  around 
€0.07 per pig.  

5.2  Practices at slaughtering and processing level 

Some  information  on  slaughtering  and  processing  was  available  from  previous  research 
but there  was less relevant literature than for farm level practices. Most slaughterhouse 
practices focused on detection. Some detection practices were unique to immunocastration 
against boar taint (see Q5), although many of the practices identified for detecting boar 
taint in entire males may also be used for vaccinated pigs.  

Several options were also identified for processing meat with detectable boar taint. These 
practices differed somewhat between countries, and their practicality will ultimately depend 
on local processing practices and the perceived consumer sensitivity to boar taint within a 
Member State.  

5.2.1  Q4  –  Techniques  and  best  practices  to  detect  boar  taint,  quantify  and 

manage positive carcasses 

5.2.1.1  State of the knowledge and comparative analysis 

The slaughterhouse practices that were identified related to: 

32 Candek-Potokar, M. et al. (2014) Testes weight is not a reliable tool for discriminating immunocastrates from entire 

males. Proceedings of the International Symposium on Animal Science 2014: 43-49. 

33 Such as measuring the level of certain substances in pigs’ blood. 

34 Civic Consulting (2013). Study and economic analysis of the costs and benefits of ending surgical castration. Part 2 – 

Country studies. European Commission. Available at: 
https://ec.europa.eu/food/sites/food/files/animals/docs/aw_prac_farm_pigs_cast-alt_research_civic_pt2-country-
studies_20131202.pdf  

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  Separation of entire males from castrated pigs; 

  Slaughter of entire males at low weight; 

  Detection of taint with the human nose method; 

  Instrumental detection methods; 

  Scales for measuring boar taint; 

  Supply chain management; and 

  Classification of tainted carcasses. 

Information  was  gathered  from  previous  work  done  on  the  topic35and  some  publicly 
available  sources  on  tests  and  services  available  for  boar  taint  detection.  Most  of  the 
information  collected  came  from  interviews  with  slaughterhouses  in  Belgium,  the 
Netherlands,  Denmark,  France  and  Germany.  No  detection  methods  or  subsequent 
practices were in use in the UK as boars are slaughtered at a low weight (105-110 kg) to 
manage  the  risks  of  boar  taint.  In  Spain,  no  detection  methods  were  identified  as  boar 
taint is addressed entirely through processing and masking. There was some evidence of 
trials  of  detection methods in the  UK,  but no  evidence of this being used  in commercial 
practice.  

The most  popular  method  among  the  slaughterhouses  that  were  interviewed  was  some 
variation of the human nose method, using a heating tool on line (slaughterline). On line 
human  nose  methods  use  different  types  of  welding  equipment,  which  can  be  broadly 
distinguished into two categories. Gas-powered soldering irons are cordless and involve an 
open flame. These were used by one slaughterhouse while another stated that it had been 
used  previously  but  was  perceived  as  difficult  and  dangerous. Electrical  tools,  which  are 
corded  and  do  not  involve  an  open  flame,  appear  to  be  used  by  the  majority  of 
slaughterhouses. These include soldering irons with metal tips and hot-air hand tools.    

Of the human nose off-line testing methods available, the hot water method was preferred 
both as a testing method for slaughterhouses that process fewer boars and as a quality 
control method for larger ones. The hot water method has also been used and validated in 
the literature36. There were also some instances of the microwave method in use, also used 
as a testing method for slaughterhouses that process fewer boars or as a quality control 
method.  

Case study: The human nose scoring system of a major Dutch slaughterhouse 

A Dutch slaughterhouse has developed its own boar taint detection method based on the 
human  nose.  The  company  an  EU  market  leader  with  over  10  years  of  experience  in 
producing  boar  meat.  It  operates  both  in  the  UK  and  in  the  Netherlands,  slaughtering 
thousands of male pigs each week.  

The Human Nose System has been selected as the preferred detection method because of 
its feasibility  and its low  costs:  in  a  slaughterhouse  with high throughput,  staff costs  to 
implement the method is under 1€ per test. Additionally, the human nose method helps 
making improvements: information is fed back to supplier, so that they can act to reduce 
boar taint incidence by adjusting feeding practices and genetic selection. The method also 
met the requirements of the slaughterhouse’s clients, and of final consumers. 

35 Nofima (2014). BoarCheck: a study on rapid methods for boar taint used or being developed at slaughter plants in 

the European Union. European Commission. Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/aw_prac_farm_pigs_cast-
alt_research_boarcheck_20140901.pdf  

36 Danish Meat Research Institute (2011). Validation of “human nose” based method for boar taint detection. Available 

at: https://ec.europa.eu/food/sites/food/files/animals/docs/aw_prac_farm_pigs_cast-alt_research_dmri_human-
nose-method.pdf 

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The method involves: 

- Checks carried out on 100% of carcasses by trained testers. 

-  The  use  of  a  flaming  soldering  iron  to  heat  the  pig’s  fat  (Weller®,  Catalog  number 
W100PG, 100 Watt); heating is done with at 370°C with a hot iron tip, 6 mm wide and 20 
mm long, for about 2-3 seconds. 

- The application on the slaughter line, at slaughter speed. 

- The use of a scoring system to classify carcasses based on the boar taint level detected.  

- The rejection of carcasses with a deviant odour. 

The scoring system for carcasses is as follows: 

0 = Normal pork smell 

1 = Deviant smell, but no boar taint 

2 = Faint boar taint 

3 = Boar taint 

4 = Strong boar taint 

Carcasses scored 3 or 4 are rejected.  

The procedure to implement the method first involves the training of testers in laboratory 
(three  days)  and  at  the  slaughterline  (five  to  six  weeks  of  experience  are  necessary  to 
achieve valid results). 

Once  trained,  each  tested  can  check  around  500  boars  per  hour.  Testers  are  regularly 
replaced (every half an hour) to avoid fatigue.  

The method is certified and quality assured. The critical elements for certification include: 

-  the use of a documented procedure,  

-  the  use  of  validated  specifications  for  testers,  defining:  sensitivity,  specificity, 
repeatability  and reproducibility, test time  per  individual  animal,  and operation  time  per 
tester. 

- the training of testers;  

- the provision of feedback to farmers; and 

- the implementation of quality controls and audits. 

There was only one mention of chemical testing being use on line in a slaughterhouse. 
This example comes from Denmark and appears to be the same example mentioned in the 
BoarCheck report in 2012. Chemical testing was identified in the BoarCheck report as being 
a preferable method for slaughterhouses processing more than 1000 boars a day (based 
on investment and maintenance costs). There were a few mentions of new on line chemical 
detection systems undergoing trials in the UK and in Denmark but no use in commercial 
practice as yet. Danish stakeholders indicated that a new chemical testing method would 
likely be ready for commercial use within the next year. Chemical testing remains limited 
and  it  is  unclear  whether  this  is  due  to  the  cost,  lack  of  suitable  technology  or  the  still 
limited need due to minimal processing of boars. Chemical testing off line is not used for 
entire males. Chemical testing was ultimately not included as a best practice as the one 
example  of  its  use  was  limited  to  a  single  slaughterhouse  and  it  does  not  appear  to  be 
considered a feasible option by any other stakeholders. 

All the interviewed slaughterhouses that deploy human nose techniques use some form of 
smell  test  assessment  and  training  for  their  staff.  Several  identified  external  consulting 
firms that provide these training services and some used in house training and testing.  

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There seems to be agreement across slaughterhouses in different countries that assessors 
need to take regular breaks and should take a break once boar taint has been detected. In 
some slaughterhouses the assessors take a break every 20 to 30 minutes. There are also 
examples  of  the  break  frequency  being  calibrated  to  the  number  of  pigs  tested.  ‘Smell 
cleansers’  such  as  coffee  or  menthol  were  mentioned  by  some  sources  but  in  the  only 
example of commercial use identified, the assessors did not tend to use the cleansers. 

Some of the larger slaughterhouses interviewed capture information on the prevalence and 
source of boar taint. One slaughterhouse in Belgium reported having used this information 
to request that a farmer with particularly high levels of boar taint in his entire males switch 
to vaccination against boar taint and then back to surgical castration. One slaughterhouse 
in  France  provided  statistical  information  back  to  farmers  to  help  them  improve  their 
processes. Elsewhere, statistical information appears to be collected and stored, but not 
necessarily analysed or fed back to farmers. Protocols for human nose testing developed 
by QS in Germany and IKB in the Netherlands, as well that developed by the ‘Beter Leven’ 
label in the Netherlands, require that information on boar taint prevalence is shared back 
with farmers.   

There have been some efforts to establish frameworks or protocols for human nose testing, 
notably  a  harmonised  effort  between  QS  in Germany  and  IKB in the  Netherlands. Such 
frameworks stipulate that if slaughterhouses wish to process entire males, they must use 
detection  methods  and  the  detection  methods  used  must  fulfil  certain  criteria.  These 
criteria do not stipulate the exact methods or procedures that must be used, but instead 
require  that  the  methods  are  well-documented,  that  staff  are  appropriately  trained  and 
that quality control procedures are in place.37 Another example of a framework or protocol 
for human nose detection is that produced by the ‘Beter Leven’ label in the Netherlands, 
which  provides  a  similar  but  slightly  more  detailed  framework  for  human  nose  testing. 
Establishing such requirements for testing can help individual slaughterhouses improve the 
consistency  and  quality  of  their  testing  and  can  also  contribute  to  improving  the 
consistency of testing between slaughterhouses.    

There were some reports of on-farm audits being used in Belgium, Germany and France. 
However, these tended to be conducted through a third party (as part of a research project 
or through a certification scheme). There was one example in France of a slaughterhouse 
conducting risk-based audits of farms.  

There  was  some  evidence  of  slaughterhouses  concluding  logistical  agreements  with 
farmers to keep sexes separate, both to make boar taint detection more efficient and to 
keep  different  categories  of  carcass  apart.  Two  slaughterhouses  in  the  Netherlands 
indicated  that  they  required  farmers  to  keep  boars  and  gilts  separate  when  they  are 
brought to the slaughterhouse. Some slaughterhouses in Germany and France have boar 
free periods during the day, where no boars are processed, to ensure that no boar meat 
enters the supply chain for certain clients.   

Slaughterhouses use a variety of systems to separate tainted boars and register boar 
taint once it is detected. Most slaughterhouses seem to use electronic systems to register 
the  presence of  boar  taint. There  was one  example of  a  slaughterhouse in  Belgium that 
also registered this information on paper. Large slaughterhouses in Germany use a system 
with  electronic  chipped  hooks  that  allows  tainted  carcasses  to  be  diverted.  One  larger 
slaughterhouse in the Netherlands marked tainted boars by tying a piece of string around 
their leg. A smaller slaughterhouse in Germany stamped tainted carcasses in addition to 
separating them with the electronic system.  

There  were  several  mentions  of  bonus  and  malus  systems  among  stakeholders 
interviewed;  this  appeared  to  be  one  of  the  biggest  areas  of  divergence  between 

37 For full details of this policy, see section 3.4.21 of QS’s guide to slaughter [in German], available at: https://www.q-

s.de/futter-tiere-fleisch/fleisch-und-fleischwaren-schlachtung-zerlegung.html  

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slaughterhouses  and  countries.  Many  slaughterhouses  pay less for  boar  meat  than they 
would for castrates or gilts. This reflects the additional cost and difficulty in both processing 
and  marketing  boar  meat,  in  spite  of  the  leaner  carcasses  (which  are  therefore  more 
valuable) of entire males. One example was found of penalties only being applied for boars 
above  a  certain  weight,  as  this  increases  the  risk  for  boar  taint.  Additionally,  weight 
frequently  plays  a  role  in  payment  systems  for  pig  meat  from  slaughterhouses.  Most 
slaughterhouses have an ideal weight range and penalise suppliers of pigs that are either 
above or  below this  range.  Previous  research  (Civic  Consulting  2013)  found  evidence of 
some  slaughterhouses  paying  bonuses  for  boars  (€1  per  carcass)  that  were  sired  using 
particular low-taint sperm. This bonus was part of a one-year trial in Germany, but is no 
longer in use. In Germany, there is currently a moratorium on penalties for boar taint until 
2019.  In  the  Netherlands,  all  interviewed  slaughterhouses  used  penalties  for  boars, 
although  these  differed  in  scale.  They  were  the  lowest  when  boars  were  intended  for  a 
better welfare label. One slaughterhouse in Belgium reported that it did not use penalties 
for boar meat as the meat would carry a better welfare label.  Penalties reported by various 
slaughterhouses include  €3,  €4 or  €5  per  boar or €0.03  per  kg of  boar meat.  Details of 
these are given in Table 9. 

Table 9.  Examples of penalties used for entire males 

Country 

Penalties used  

Other notes 

Belgium (slaughterhouse 1) 

No penalties used 

Beter leven label 

Belgium (slaughterhouse 2) 

Penalty on boars that 
are too heavy 

Netherlands (slaughterhouse 1) 

Penalty of 4 EUR per 
boar carcass 

No boar taint detection 
used 

Netherlands (slaughterhouse 2) 

Penalty of 3 EUR per 
boar carcass 

Higher welfare label, boar 
taint detection used 

Netherlands (slaughterhouse 3) 

Penalty of 5 EUR per 
boar carcass  

Boars not part of welfare 
label, boar taint detection 
used 

Germany (slaughterhouse 1) 

Penalty of 0.03 EUR 
per kg of boar meat 

For boars imported from 
the Netherlands 

Germany (slaughterhouse 2) 

No penalty used 

For boars from Germany 

France 

Penalty associated 
with the detection of 
boar taint in the 
carcass 

Penalties for boar taint 
vary depending on the 
genetic profile of the 
animal 

Slaughterhouses’  use  of  bonus  -  malus  systems  is  generally  linked  to  the  availability  of 
markets in which they can sell that meat. Therefore, although it is a practice undertaken 
by  slaughterhouses,  the  decision  to  use  bonuses  or  maluses  is  inevitably  based  on  the 
price slaughterhouses will receive for the meat from the end customer. Bonuses may also 
come from further up the supply chain. For example, Delhaize (a retailer) in Belgium offers 
farmers a €1 bonus per pig for participation in a particular pork quality label (which included 
a no-castration policy). This is possible for Delhaize because consumers are willing to pay 
more  for  pork  carrying  this  label.  In  markets  where  boar  meat  is  still  considered 
unacceptable  by  the  end  consumer  or  where  value  has  not  been  added  through  better 

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welfare schemes, it is impossible for slaughterhouses to change their payment system to 
encourage boar fattening without impacting their own economic viability. As such, the use 
of payment schemes and bonus-malus systems is often a function of the market. Using a 
penalty system that specifically penalised tainted carcasses could be used  to incentivise 
farmers to invest in feeding, breeding or housing solutions, and for this reason could be 
considered  a  best  practice. The only  example of  this happening  was  documented  in one 
large integrated supply chain in France. A penalty system based on boar taint also reflects 
the  reduced  returns  tainted  carcasses  receive  on  the  market.  For  example,  one  study38 
estimated that tainted carcasses in the Netherlands return around €25 less than their non-
tainted counterparts.  

While  several  slaughterhouses  appeared  to  have  systems  and  procedures  in  place  for 
monitoring  complaints  from  customers,  no  slaughterhouses  reported  having  received 
any complaints related to boar taint.  

The  field  identified  a  number  of  methods  for  dealing  with  tainted  carcasses.  Some 
carcasses are sold into specific markets. For example, the UK and Scandinavian countries 
were mentioned by one source as being more accepting of tainted meat. Italy and Asian 
markets  were  cited  as  examples  where  boar  tainted  meat  cannot  be  sold.  One 
slaughterhouse in the Netherlands stated that they did not use or process tainted meat. 
Some slaughterhouses indicated that they use this meat for pet food or in certain processed 
products. One slaughterhouse in France indicated that they sell all tainted carcasses to a 
specific partner. 

5.2.1.2  Data gaps 

There was little evidence of commercial use of chemical testing of boar taint among the 
slaughterhouses interviewed. There was one mention of the PTR-TOF-MS39 technique being 
under trial, but no commercial use as yet.   

Little to no information was received on the costs of the various practices. Some have 
been assumed to require more investment in equipment or labour, but it is not clear how 
far these practices are actually feasible, in particular for slaughterhouses of different sizes 
or in different Member States.  

The hot water method was the only technique in use off line. Other methods identified in 
the literature and used in studies, such as the microwave method, were not used by any 
of the slaughterhouses interviewed. It is not clear why this method is preferred.  

The practices of using smell cleansers and sex separation emerged during the research 
and  had  not  been  previously  identified  in  the  literature  review.  For  this  reason,  not  all 
slaughterhouses interviewed were asked about these practices and there may be missing 
information about the extent and variation of their commercial use.  

Few  slaughterhouses  that  were  interviewed  did  not  report  statistics  quantifying  the 
incidence  of  boar  taint.  A  very  large  range  was  reported  by  one  slaughterhouse,  which 
claimed  that the  percentage of  tainted  boars  varies  between  0.5%  and  6%  per  day  and 
between  0%  and  10%  per  batch.  Others  have  reported  incidence  rates  of  1%,  3%  and 
between  2  and  3%.  Research  conducted  in  the  Netherlands  has  measured  an  incidence 
rate of slightly more than 3%. 

38 Backus, G. (2018) Whole chain approach for moving from surgical castrate to entire male production.  

39 Proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS) is a technique used to measure volatile 

organic compounds in air.  

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Case study: Harmonisation of standards for HNS in Europe - The case of QS and 
IKB 

In  2012,  two  European  quality  assurance  organisations,  QS  in  Germany  and  IKB  in  the 
Netherlands  agreed  on  a  common  framework  for  boar  taint  detection  using  the  Human 
Nose Scoring (HNS) system. This additional harmonised framework represents an addition 
to the standards already shared by the two assurance schemes as both organisations, who 
adopt  a  supply  chain  approach  to  certification,  provide  standardised  frameworks  for 
different  activities  along  the  pork  chain.  The  framework,  while  not  going  into  detail 
regarding the specific methods and parameters that companies must follow, specifies the 
overall criteria needed when slaughtering entire males to ensure the reliable detection of 
carcasses with potential boar taint. Companies slaughtering entire males must: 

•  Have  instructions  on  how  the  detection  system  is  implemented  and  carried  out  test 

procedures;  

•  Specify and document the sensitivity, specificity and repeatability of the test procedure;  

•  Document the method used to determine the validity of the performed tests; 

•  Specify and document the test times per individual animal and maximum continuous 

testing time per test person; 

•  Define  and  implement  the  procedures  for  the  monitoring  of  test  persons  and  the 

performance of parallel controls. 

•  Train employees selected to detect  boar taint  adequately (initial training and  regular 

further training).  

•  Document content and frequency of training. 

• 

• 

Implement  and  document  separate  logistic  processes  for  the  separation  of  tainted 
carcasses  

Implement  and  document  correction  and  prevention  measures  in  case  of  deviations 
from established procedures 

•  Report findings of each batch tested back to the farmer/sender. 

The  implementation  of  the  framework  and  compliance  to  the  criteria  is  carried  out  by 
regular  random  audits  of  slaughterhouses  adhering  to  the  QS/IKB  certification  schemes 
which also slaughter entire males. As part of the bilateral agreement between QS and IKB, 
QS is authorised to carry out random and regular audits abroad in the Netherlands. These 
abroad checks also have the function to review the functionality of the assurance scheme 
more broadly and identify further optimisation and harmonisation measures required. 

5.2.2  Q5 – Techniques and best practices to obtain assurance from farmers that 

vaccinated pigs do not contain detectable boar taint 

5.2.2.1  State of the knowledge and comparative analysis 

The following types of practices were identified: 

  Random checks for boar taint; 

  Checks based on testes measurement; 

  Checks based on bulbourethral gland measurement; 

  Chemical testing of samples from a small number of pigs; 

  Documented record of vaccinated pigs; 

  Bonus payments to farmers who vaccinate their pigs against boar taint; and 

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  Testosterone tests. 

Unlike entire males, not all vaccinated pigs are tested in the slaughterhouse. Checks for 
boar taint among vaccinated pigs tend to be risk-based or randomly sampled.  

Risk-based assessment is sometimes done by observing the size of the testicles, either 
visually or by measuring them against a threshold. This observation can be done either on 
line  or  when  the  pigs  first  arrive  at  the  slaughterhouse.  However,  although  this  was 
reported as being used by some slaughterhouses, it is not considered to be an effective 
method  for  determining  whether  the  vaccine  has  been  successful.  This  is  due  to  the 
variation in testes sizes between individual pigs, even within the same breed. Studies have 
also confirmed that the weight of the testes is not a reliable measurement for determining 
the effectiveness of vaccination against boar taint.40  

The  size  of  the  bulbourethral  gland  can  also  be  checked.  Studies  have  shown  that  the 
bulbourethral gland can be a reliable indicator of the success of the vaccination41 and some 
evidence was found of this method being used in Norway. However, due to the relatively 
small  size  of  the  gland  and  the  likelihood  of  it  being  damaged  during  butchering,  this 
practice was not included in the final document.  

Risk-based assessment can be done using testosterone testing, as testosterone levels tend 
to  correlate  with  androstenone  levels.  This  can  be  used  on  batches  of  pigs  to  identify 
potentially  at-risk  groups  and  was  recommended  as  a  practice  by  the  vaccine 
manufacturer. It has been used by some slaughterhouses in Belgium and Germany.  

For vaccinated pigs, boar taint is usually detected with the same methods used for 
entire males. In Norway, however, chemical testing of androstenone is used. Around one 
per cent of carcasses are sampled based on risk factors and fat samples are collected and 
sent  to  a  laboratory  in  Germany.  This  is  done  because  it  is  thought  that  human  nose 
techniques are not necessarily accurate enough and there is a sense that the Norwegian 
public is highly sensitive to boar taint. 

One vaccine manufacturer recommended that farmers provide documentation of when 
vaccines  were  given,  records  of  any  abscesses,  abnormal  behaviour  and  information  on 
the  transport  of  pigs  post-farm.  This  is  done  in  Norway,  where  all  such  documentation 
must also be signed off by a veterinarian. 

Slaughterhouses differed in how they paid for vaccinated pigs. In Norway, a steep penalty 
(around €300) is applied for  any  vaccinated  pigs that  come  back positive  for  boar taint. 
This  has  acted  as  a  disincentive  to  farmers  and  has  contributed  to  the  reduced  use  of 
vaccination  against  boar  taint  in  Norway.  In  the  Netherlands,  one  slaughterhouse 
confirmed  that  vaccinated  pigs  were  given  the  same  standard  penalty  as  boars  (€4  per 
carcass). In Belgium, slaughterhouses stated that for some labels, vaccinated pigs received 
a bonus payment. One source quantified this at €0.01 per kg. 

5.2.2.2  Data gaps 

There  are  several  gaps  in  the  information  on  vaccination  against  boar  taint  in 
slaughterhouses, largely due to the fact that this is not yet widely practiced.  

No  detailed  information  was  found on slaughterhouses conducting audits of farms, 
although one slaughterhouse reported that farms were audited by a third party. There is 
also no evidence of slaughterhouses discussing other aspects of vaccination against boar 
taint (such as the use of specific feeds or rearing practices) with farmers.  

40 Candek-Potokar, M. et al. (2014) Testes weight is not a reliable tool for discriminating immunocastrates from entire 

males. Proceedings of the International Symposium on Animal Science 2014: 43-49.  

41 Ibid. 

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From  the  limited  amount  of  information  received  on  payment  for  vaccinated  pigs,  it 
appears there are significant differences in practice and that this may impact the economic 
feasibility  of  vaccination  against  boar  taint  for  farmers.  More  information  on  how  the 
practices compare to the payment systems used across multiple slaughterhouses would be 
helpful.  

There  were  also  gaps  in  information  on  how  vaccination  against  boar  taint  is 
documented  and  how  this 
farmers  and 
slaughterhouses.  It  was  not  clear  how  routine  this  practice  is  or  whether  any  electronic 
systems are used to document vaccination against boar taint and pass back information 
on the outcomes of vaccination to farmers.  

transmitted  between 

information 

is 

5.2.3  Q6 – Techniques and best practices to deal with meat with detectable boar 

taint 

5.2.3.1  State of the knowledge and comparative analysis 

In all the Member States in which information was collected, tainted carcasses are usually 
sorted  at  slaughterhouse  level  prior  to  processing.  Processors  do  not  verify  the 
quality of the meat supplied  to them. Processors do not  quantify what proportion of the 
meat  received  from  slaughterhouses  is tainted.  Typically, slaughterhouses  would  specify 
the  properties  of  the  meat  to  their  providers,  or  in  some  instances,  slaughtering  and 
processing are integrated and the same actor is responsible for both. 

Although  the final  document focuses  solely on the  management of meat  with  boar taint 
during processing, many stakeholders raised issues related to processing meat from entire 
males that have little to do with the presence of taint. There are many other factors related 
to the quality of meat that require attention when processing entire males. Examples are 
the  ratio  of  fat  to  lean  meat,  pH  levels,  tenderness  and  fat  quality  (e.g.  the  degree  of 
unsaturation,  and  iodine  value).  There  are  also  concerns  regarding  the  production  of 
certain  products  with  highly  particular  specifications,  such  as  Protected  Designation  of 
Origin  (PDO)  products.  Vaccination  against  boar  taint  has  been  trialled  as  a  potential 
solution  for  producing  meat  that  better  meets  the  quality  requirements  for  certain 
processed products, but with mixed results. As mentioned earlier, the use of vaccination 
against boar taint for the production of Parma ham has proven to be of limited benefit to 
producers, because a large proportion of carcasses end up being rejected as non-compliant 
with the PDO standards. These concerns, and solutions to address them, were out of scope 
of the study, but are important to highlight as any processor looking to transition to entire 
males has to address them. 

The  research  found  that  processors  across  various  Member  States  are  using  different 
techniques to mask boar taint in final meat products. These techniques enable the sale and 
consumption  of  tainted  meat  in  various  markets,  including  those  where  consumers  are 
sensitive to boar taint. 

Stakeholders in Germany reported that dilution, fermentation and smoking of tainted 
meat are used in their country to mask boar taint in the final product. Examples of boar 
tainted meat being used in pet food were reported in Germany. Stakeholders had mixed 
responses to the use of tainted meat in pet food, citing the fact that this was becoming 
less  acceptable  to  the  pet  food  industry  and  that  the  objectives  of  the  initiative  are  to 
provide meat for human consumption and enhance the prospects of producers to sell meat 
from entire males or vaccinated pigs to consumers. Therefore, use of tainted meat for pet 
food has not been included in final version of the document. Thermal treatment is used 
by  processors in both Germany and Spain. Spices are used in Spain to mask boar taint 
while marinating tainted meat and dilution is used in Denmark. 

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Tests conducted in Denmark have shown that it is not possible to remove the boar taint 
from meat by dry curing42. It was shown that dry curing increases the concentration of 
the boar taint taste in the final product. In Spain, by contrast, stakeholders have reported 
that boar taint can be reduced by producing marinated meat and chorizo through a dry-
curing  process.  Dry  curing has  been included in  the  final version of the  documents,  but 
with the caveat that there have been mixed experiences with its effectiveness.  

5.2.3.2  Data gaps 

There are several gaps in the information on how processors deal with tainted meat.  

The  extent to which different methods used to mask boar taint are effective  for 
certain levels of taint is unclear. There is a lack of quantitative information about methods 
reported,  such  as  the  exact  proportion  of  tainted  to  non-tainted  meat  that  needs  to  be 
used to dilute boar taint, or the optimal level of spices needed to mask a certain degree of 
boar taint. There is often a lack of detail on specific methods (what spices are used to mask 
boar taint, at what temperature the meat should be cooked to avoid boar taint, etc). As 
there are many factors involved in processing, and each processed product will be subject 
to  different  processes,  it  is  not  surprising  that  there  is  a  lack  of  specific  or  quantifiable 
information. And this information is unlikely to be shared by many processors as it relates 
to the specific methods and recipes used in production.  

The impact of methods used to reduce boar taint on the market value of products is not 
clearly documented either. For example, does mixing tainted meat with non-tainted meat 
reduce the final price of products? Do certain methods of processing result in higher-priced 
or premium products?  

There is also a lack of information  about consumer acceptance  of  products  processed 
with tainted meat. 

Finally,  no  examples  were  identified  of  the  following  techniques:  injection  of  brine, 
techniques to strip fat from meat and the use of liver. Techniques to strip fat from 
the  meat  were  mentioned  by  stakeholders  during  the  consultation  process,  but  such 
processes are costly and it is not clear whether this is currently occurring in commercial 
conditions in the EU.  

5.3  Practices at retailing and food service level 

For both entire males and vaccinated pigs, it was difficult to identify practices in retail and 
food  service.  There  was  little  available  information  in  the  literature  and  companies  are 
generally unwilling  to communicate  about this  issue.  Many  consumers  are  not  aware  of 
piglet castration and boar taint.  

Practices at retailing and food service level are largely dictated by firms’ understanding of 
the  consumer  acceptance  of  boar  taint.  There  has  been  some  exploration  of  this  in  the 
literature through  cross-country or single-country studies looking for  potential threshold 
values for androstenone and skatole.  

42 Claudi-Magnussen, C., Kristensen, L., and Tørngren, M. Use of tainted boar meat for processed meat products. 

Danish Meat Research Institute. Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/aw_prac_farm_pigs_cast-alt_emp_use-of-tainted-boar-
meat.pdf  

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5.3.1  Q7 - Techniques and best practices to increase the market value of meat 
from uncastrated pigs and to prevent meat with detectable boar taint to be 
on the shelves or served   

5.3.1.1  State of the knowledge and comparative analysis 

The use of an agreed set of specifications for suppliers was the main technique used by 
retailers  to  avoid  boar  tainted  meat  reaching  their  customers.  Specifications  prohibit 
castration,  impose  specific  breeding  or  feeding  techniques,  or  require  certain  housing 
conditions.  Auditing  or  farm  inspections  may  be  used  to  ensure  compliance.  The  use  of 
buyer  specifications  related  to  castration  policies  was  found  in  Germany,  Denmark,  the 
Netherlands,  the  UK  and  Belgium.  These  specifications  are  sometimes  linked  to  certain 
animal welfare standards and product labels, some of which set specific requirements on 
non-castration. Examples include: 

  Red Tractor Assured Food Standards43 and 'RSPCA'44 assurance labels are based on 
schemes  that  do  not  allow  castration  in  the  pork  supply  chain.  These  labels  are 
widely recognised and used by consumers in the UK.   

  The  BMPA's  British  Quality  Assured  Pork45  (BQAP)  label  does  not  allow  for  the 
slaughter of males over 100 kg. This is specifically aimed at avoiding boar taint.  

  The  Beter  leven  –  Een  ster46  (Live  better  –  One  star)  assurance  scheme  in  the 
Netherlands forbids surgical castration. This standard is applied to pig meat products 
sold  in  retail  markets.      The  “Beter  leven”  label  also  includes  a  requirement  for 
slaughterhouses to use boar taint detection.  

  The  QS  assurance  scheme  in  Germany  and  the  IKB  assurance  scheme  in  the 
Netherlands do not forbid castration but allow for the inclusion of meat from entire 
males so long as detection techniques are used. For this purpose, QS and IKB have 
also developed a framework for human nose boar taint detection (for further details 
on this, see Q4).  

  In  addition  to  specifying  standards,  standard  owners  or  retailers  may  provide 
guidance to parts of the supply chain looking to transition to producing boar meat. 
For  example,  QS  in  Germany  has  developed  a  guide  for  farmers  that  includes  a 
checklist  to  help  determine  whether  farming  conditions  are  already  suitable  for 
raising boars or whether any alterations need to be made.47  

In  France  one  producer  (integrating  farmers,  feed  vendors,  slaughterhouses  and 
processors) has provided assurance to retailers and business-to-business (B2B) buyers by 
organising  visits  and  demonstrations  of  the  human  nose  detection  method,  sharing 
information  about  annual  third  party  audits  of  its  human  nose  detection  protocol,  and 
running pilots in close collaboration with store managers at retail shops. 

Existing techniques used by retailers to increase the value of meat from uncastrated pigs 
include marketing campaigns and export to specific markets.  

Retailers  in  the  UK  and  the  Netherlands  have  indicated  that  marketing  messages 
addressed  to  consumers  generally  do  not  mention  castration  issues.  These  messages 
generally  mention  broader  better  animal  welfare  standards;  more  specific  references  to 
non-castration  are  only  available  to  consumers  interested  enough  to  read  their  animal 

43 https://assurance.redtractor.org.uk/  

44 https://www.rspcaassured.org.uk/about-us/  

45 http://britishmeatindustry.org/our-work/bmpa-pork-scheme/  

46 https://beterleven.dierenbescherming.nl/varken-2sterren  

47 This guide is available through the QS website [in German]: https://www.q-

s.de/services/files/mediencenter/publikationen/QS_Jungebermast_A5_web_RZ.pdf  

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welfare purchasing policies.48 Retailers are generally very reluctant to communicate about 
non-castration practices to consumers and so meat from uncastrated pigs is not specifically 
differentiated.  

This is not universally the case, however. In Belgium Delhaize has recently included and 
publicised a ‘castration free’ policy for one of its pork labels.49 The marketing for this label 
highlights the absence of castration, but also mentions several other aspects of this label: 

  The meat has been carefully selected for taste, and comes from a specific low-taint 

breed 

  Pigs are fed a balanced diet which also contributes to human health (through the 

inclusion of omega-3 fatty acids)  

  The production is entirely Belgian and farmers receive an incentive per animal and 

reimbursement for additional feed costs; and 

  There is a lower need for antibiotic use and therefore reduced use of antibiotics in 

the rearing of the pigs.   

  Rather than referencing it as part of a broader animal welfare policy, this example 
includes non-castration and better welfare alongside taste, quality, human health, 
an appeal to supporting local farmers and environmental concerns.  

Another way to increase the value of meat from uncastrated pigs with detectable boar taint 
is to sell it in markets where the acceptance of boar taint is higher than in the producers’ 
domestic  market.  The UK  is  often  cited  as  an  example  where  tainted  meat  may  have  a 
market. However, this was disputed as a best practice by stakeholders who felt that there 
is no such thing as a market with higher acceptance of boar taint and that this should not 
be considered a solution for the problem of tainted meat.  Denmark is a special case, as a 
lot  of  pork  meat  from  the  country  is  exported,  including  to  Asian  countries  where 
consumers are very sensitive to boar taint. This complicates any potential transition to the 
production of entire males.   

Retailers deal with customer complaints which may or may not be linked with boar taint. 
In some cases, complaints may help monitor the effectiveness of measures implemented 
to  prevent  boar  tainted  meat  from  reaching  consumers.  This  may  help  retailers  take 
informed decisions about problems arising within the value chain. However, no evidence 
was found of this information being used effectively by retailers to deal with boar taint on 
a routine basis. Although all retailers will have a system for managing complaints, it may 
be  difficult to determine whether complaints are related to boar taint or to other issues 
with the meat, and no evidence was found of retailers passing this information on further 
down the supply chain. For this reason, this practice was not included in the final version 
of the documents.  

5.3.1.2  Data gaps 

The data needed to determine whether meat labelled according to animal welfare standards 
is sold at higher prices in countries where these standards have been reported were not 
available. It  is  also  not  clear  whether  exporting  meat  to  different  market  places creates 
challenges  (e.g.  increased  costs  for  transport)  or  provides  opportunities  (e.g.  higher 
pricing). More quantitative information is needed to address this gap. 

There  was  little  evidence  of  retailers  using  complaint  management  to  monitor  the 
effectiveness of the measures put in place to avoid boar tainted meat ending on shelves.  

There was no information on checks made by buyers on behalf of supermarket chains 
that could be used to prevent tainted meat from reaching consumers. The converse was 

48 See, for example, the national animal welfare purchasing policy of Aldi in Germany, available at: https://www.aldi-
nord.de/unternehmen/verantwortung/lieferkette-food/tierwohl-bei-aldi-nord/tierwohl-einkaufspolitik.html  

49 Delhaize. (2018) Delhaize kiest voor exclusief varkensras met nog meer smaak en nog meer oog voor dierenwelzijn. 

Available at: https://www.delhaize.be/press_overview:exclusief-varkensras   

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observed,  whereby  suppliers  invited  retailers  to  demonstrations  of  their  protocols  for 
detecting  boar taint, largely to convince the latter to accept  meat  from  entire  males on 
their shelves. 

Case study: Delhaize’s successful marketing of meat from non-castrated pigs 

In  June  2018,  Belgian  retailer  Delhaize  launched  its  new  castration-free  pork  products 
under  its  “Better  for  Everyone”  (Mieux  pour  Tous  /  Beter  voor  Iedereen)  label,  a  label 
established in 2014 with a focus on nutritional quality and sustainability. The label is based 
on four pillars, namely: 100% Belgian production, better taste, better animal and human 
nutrition, and better animal welfare. The non-castration clause was introduced as a new 
element  of  the  label,  with  the  first  meat  products  from  non-castrated  pigs  available  for 
purchase in selected stores in March 2018. Since then the availability of non-castrated pig 
meat  has  expanded  and  at  present  all  pork  meat  sold  in  Delhaize  supermarkets  is  sold 
under the “Better for Everyone” labels and is therefore non-castrated.  

To make the transition to non-castrated pig meat, Delhaize implemented various changes 
within its supply chain. First of all, in order to work closely will all actors along the chain 
and  achieve these  changes,  all  pig  producers,  feed companies  and  slaughterhouses  who 
follow the “Better for Everyone” label standard must join the Healthy Farming Association 
established by Delhaize. This network of supply chain actors was created to improve the 
sustainability of the food chain with a specific focus on animal feed. To date this network 
includes 208 Belgian pig producers. Furthermore, Delhaize created a double incentive for 
farmers to produce according to Delhaize’s standards: they guarantee the purchase of a 
certain  volume  of  the  farmer’s  production,  and  they  also  pay  a  higher  price  for  the 
carcasses  compared  to  the  market  average.  More  specifically,  farmers  receive  an  extra 
€3.59 per produced pig, of which €2.59 will be full compensation for higher costs associated 
to the special feed formula rich in omega-3 that farmers are required to use, and €1 will 
be the bonus.  

To  minimise  the  presence  of  boar  taint  in  its  meat  Delhaize  implemented  a  number  of 
technical changes in the breeding, rearing and slaughtering stages of its pork supply chain. 
The first technical solution was the use of selective breeding. Delhaize selected a specific 
“bouquet”  variant  of  the  Piétrain  breed  from  Flemish  company  DANIS  and  its  artificial 
insemination  centre  KI  Lichtervelde,  which  benefits  from  the  expertise  of  big  breeding 
company PIC. This Belgian pig breed was selected because it does not develop boar taint 
as  much  as  other  breeds,  while  also  fitting  with  the  focus  on  Belgian  products  and 
production of Delhaize’s “Better for Everyone” label. The specific bouquet variant is only 
exclusive to Delhaize and pig producers can only use this breed with the retailer.  

Delhaize also established clear guidelines that pig producers need to follow when rearing 
the  pigs  for  slaughter.  Implementation  of  the  guidelines  are  monitored  via  regular 
inspections and the use of Tracy from Belpork, a digital registration and traceability system 
that allows all members along the chain to track and input information, including inspection 
outcomes. Nutritional quality of the meat is regularly checked and samples are analyzed 
in the independent laboratory of UGent. According to the guidelines, male and female pigs 
must be reared separately as the sight or smell of gilts might increase the level of hormones 
linked to boar taint in males. Moreover, pigs must be fed the specific feed formula provided 
by  AVEVE-Dumolin,  made  up  of  local  cereals  and  flaxseed  rich  in  omega-3.  While  this 
special feed is used specifically to reduce boar taint, this is not mentioned by Delhaize as 
a  benefit  of  the  special  diet  fed  to  pigs.  Instead  Delhaize  states  that  this  specific  feed 
composition  improves  the  taste  of  the  meat  and  improves  pigs’  health  and  welfare  by 
reducing the need for medication and antibiotics. Delhaize also states that this special diet 
increases  omega-3  in  the  meat,  offering  additional  health  benefits  to  consumers.  No 
changes  were implemented for the  slaughter  weight of  entire males,  which remained  at 
110kg. 

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Finally,  Delhaize  also  implemented  technical  changes  during  slaughter.  The  retailer 
introduced  detection  measures  on  the  slaughter  line  by  requiring  the  use  of  trained 
assessors to identify tainted carcasses. To do this, the assessors heat up a sample of pig 
fat  with  a  gas-powered  soldering  iron  and  smell  it  to  detect  boar  taint.  If  boar  taint  is 
detected, the carcass is removed from the slaughter line and is redirected to another value 
chain for pork meat not sold as fresh meat for cooking. Of the pig meat produced according 
to the “Better for Everyone” standards, 45% is sold as fresh meat and 55% as processed 
meat.  Delhaize  states  that  by  implementing  the  above-mentioned  changes  in  breeding, 
rearing and slaughtering in its pork supply chain, boar taint affects approximately 2% of 
the 6000 to 8000 pigs slaughtered weekly for its supermarkets.  

Overall,  the  changes  made  by  Delhaize  have  been  welcomed  by  politicians,  NGOs,  and 
supply  chain  actors  who  perceive  the  use  of  entire  males  as  an  improvement  of  the 
retailer’s commitment to increased animal welfare.  Moreover, Delhaize has been able to 
market  non-castrated  meat  successfully to  customers  by  focusing on  provenance, taste, 
health benefits and animal welfare. In promoting the improved “Better for Everyone” label, 
Delhaize  highlighted  the  benefits  of  using  meat  from  the  100%  Belgian  Piétrain  breed, 
describing  its  meat  as  tender,  flavoursome,  juicy  and  of  superior  quality.  These  claims 
were backed by taste panels conducted prior to the launch which showed that customers 
found the meat tastier than before. Secondly, the “Better for Everyone” label present on 
the meat packaging predominantly promotes the health benefits of consuming meat rich 
in omega-3 resulting from the flaxseed-rich diet fed to pigs. The focus on the additional 
animal welfare benefits resulting from non-castration, while mentioned on its site and in 
the media, do not seem to be the main focus of its product marketing to consumers. Lastly, 
Delhaize does not sell its “Better for Everyone” products at a premium, making the new 
improved pork meat accessible to all its customers.   

Case study: Lidl Belgium’s move to entire males 

In 2012, Lidl Belgium decided to move fully to the sale of meat from entire, non-vaccinated 
pigs.  This  was  a  decision  that  applied  only  to  Lidl  Belgium  rather  than  the  broader  Lidl 
group. This change was due to Lidl’s focus on animal welfare standards, and to the broader 
political context in Belgium – characterised by increased media attention to the matter of 
animal  welfare.  Lidl  Belgium  was  also  interacting  regularly  with  the  Non-Governmental 
Organisation GAIA, which raised the question of pig castration.  

The transition took place within a short period of three months. Lidl Belgium engaged with 
its suppliers to ask them to move to the production of entire males. A number of farmers 
providing  meat  to  Lidl  Belgium  were  already  working  with  entire  males  at  the  time, 
therefore this facilitated the transition for the whole supply chain.  

There was a feeling among farmers that the production of entire males presented various 
disadvantages, such as increased fragility and propensity to suffer from cold temperatures, 
greater aggressiveness, and more frequent injuries. However, farmers have embraced the 
transition on the basis of the benefits it has brought them: abandoning the act of castrating 
piglets, not having to manage the risks of wound infection in castrated piglets, and seeing 
non-castrated pigs grow with less food than is required in castrated pigs. There were no 
monetary incentives offered to farmers to help them transition towards the production of 
entire males.  

Slaughterhouses  hired  additional  staff  to  perform  smell  tests  on  the  carcasses  so  as  to 
detect boar taint. Boar tainted carcasses are stored separately, and the meat undergoes 
further processing. It is not sold as fresh meat to consumers. 

Lidl Belgium has never communicated specifically on the issue of non-castration on labels 
of products sold to consumers. It has been reported elsewhere, such as on Lidl Belgium’s 

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website. Nowadays, Lidl Belgium has also included a new label on its products, the ‘Beter 
Leven’ label. This includes also non-castration as one of several other aspects / benefits. 

5.3.2  Q8 - Techniques and best practices to increase the acceptance of meat from 
vaccinated  pigs  among  consumers  and  to  prevent  meat  with  detectable 
boar taint to end on the shelves or served   

5.3.2.1  State of the knowledge and comparative analysis 

The  reliance  on  an  agreed  set  of  specifications  (among  which  the  obligation  to  use 
vaccination  with  Improvac  for  all  piglets)  was  the  only  documented  technique  used  by 
retailers to avoid boar tainted meat ending on shelves at retail stores. Belgium is the only 
country  where  a  retail  company  (ColruytGroup)  has  reported  sourcing  its  meat  from 
vaccinated pigs. The company has embraced immune-castration in 2010 and has deployed 
this across all its brands (Okay, Bio Planet, Spar, Cru, etc.).  

Farmers  are typically  visited  by  an  independent organisation  once  a  year  to  control that 
they respect the specifications agreed upon. Additional audits are also conducted every 
year on a random basis by ColruytGroup. The company is supported by technical experts 
that  offer  training  to  animal handlers  on  the  use  of  Improvac,  the  treatment  of  piglets, 
livestock keeping, and animal welfare issues.  

ColruytGroup communicates about vaccination against boar taint in combination with other 
messages  on other  benefits to  positively  position itself  as  caring  for  animal  welfare, pig 
health  and  sustainability.  While  the  retailer  is  very  reluctant  to  use  the  term 
“immunocastration”,  it  uses  the  word  “vaccination”  in  all  its  communications  to 
consumers (website50, short videos at the butcher shelves, bi-weekly customer folders, 
consumer complaint service, etc.).   

Like  for  non-castration,  retailers  sourcing  their  meat  from  vaccinated  pigs  deal  with 
consumer  complaints  which may or may  not be  linked  with  boar taint.  In  some  cases, 
consumer management methods may help monitor the effectiveness of measures put in 
place  to  prevent  boar  tainted  meat  from  reaching  shelves.  Although  consumer 
management can only be used ex-post, it may help retailers take informed decisions about 
problems arising within the value chain.  

Case study: Colruyt’s successful transition to vaccination against boar taint 

In  2010,  Colruyt conducted  a  trial to  improve pigs’  welfare  by using  vaccination  against 
boar taint. It used Improvac on approximately 2,600 boars and monitored all production 
steps from vaccination to meat consumption. The trial involved the gathering of information 
on various implications from transitioning to vaccinated pigs, such as profitability for pig 
producers,  meat taste  and fat  content,  and  consumer  reactions.  The study  was  done in 
cooperation with the Flemish Research Institute for Agriculture, Fisheries and Food (ILVO).  

Colruyt’s trial revealed several advantages of vaccination compared to physical castration: 
better animal welfare, better feed efficiency and reduced manure production. Additionally, 
no  surgery  is  required  with  vaccination.  This  technology  therefore  reduces  the  risk  of 
infection, and antibiotics are needed less often. Meat from vaccinated pigs is also leaner 
than  pork  from  castrates.  Panels  involved  in  tasting  tests  were  not  able  to  distinguish 
between meat from castrates and meat from Improvac-vaccinated animals. There was a 
small preference for the pork from vaccinated pigs.  

Based  on  these  results,  Colruyt  discussed  the  plan  to  implement  vaccination  with  its 
suppliers,  and  addressed  any  suppliers’  concerns.  Following  these  discussions,  Colruyt 

50 https://www.colruytgroup.com/wps/portal/cg/en/home/stories/Welfare-pigs   

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decided  to  include  vaccination  against  boar  taint  as  a  mandatory  requirement  for  its 
suppliers.  

Based  on  Colruyt’s  requirements,  it  is  the  responsibility  of  slaughterhouses  to  recruit 
farmers that use vaccination. When slaughterhouses detect boar taint, Colruyt encourages 
them to contact the farmer and assess whether vaccination has been done correctly. Zoetis 
can help farmers address problems. 

Colruyt conducts targeted  and  random  checks  for  boar  taint, including taste checks  and 
laboratory analyses. The transition to vaccination did not increase Colruyt’s costs for supply 
chain controls: checks for boar taint are integrated into existing meat quality controls. The 
use of vaccination did not result in any negative impacts on pork sales.  

Colruyt  does  not  mention  vaccination  on  its  products’  packaging:  its  policy  is  to  avoid 
unnecessary  messages  on  packaging,  as  these  may  confuse  the  consumer.    It  rather 
communicates  the  use  of  vaccination  by  other  means,  such  as  press  releases,  in-store 
videos, and its webpage. The use of vaccination is accompanied by messages on improved 
animal welfare. In its communications to consumers, Colruyt does not use technical words 
such as “immuno-castration”, but rather uses “vaccination”, which is more understandable 
to consumers. Consumers’ reactions to these campaigns were limited and mainly positive 
because of the improved animal welfare implications from vaccination. 

When transitioning to vaccination, Colruyt’s biggest challenge was to convince farmers to 
change  their  practices.  To  address  this,  Colruyt  developed  a  communication  plan  in 
cooperation with Zoetis to inform farmers of the vaccination technology, its application and 
its advantages. Zoetis offers technical support and training to farmers. 

5.3.2.2  Data gaps 

There  were only  few  examples found  in  Europe  of  retailers  having opted  for  meat  from 
vaccinated pigs. This issue is not targeted specifically by retailers in their communication 
to  consumers.  It  is  therefore  difficult  to  see  if  there  is  any  consumer  acceptance  of 
products  processed  with  meat  from  vaccinated  pigs  and  what  potential  impact  higher 
consumer awareness on this issue would have on prices.  

There  was  little  evidence  found  of  retailers  having  used  complaint  management  to 
monitor the effectiveness of the measures put in place to avoid boar tainted meat ending 
on shelves.  Only  one  retail company  (ColruytGroup)  has  reported that  client  complaints 
may lead the company to block the whole production line if the company suspects that a 
specific  delivery  contains  boar tainted  meat.  This  is  part  of  ColruytGroup’s  strict  quality 
procedure and was said to be extremely rare for boar taint. 

5.4  Summary of initial findings and results of the data gathering 

Although  certain  practices seem to  be  widespread  (for  example,  slaughtering  boars  at  a 
lower  weight),  there  seems  to  be  significant  heterogeneity  in  the  approaches  to  raising 
boars or vaccinated pigs used across Europe. Much of the variation seems to stem from 
the attitude toward the problem of boar taint itself and retailers’ views on how acceptable 
boar taint is perceived to be to the end consumer.  

The extent to which these assumptions about sensitivity or lack thereof are grounded in 
evidence remains unclear. There was no evidence of consumer complaints about boar taint 
and many consumers are not aware of the issue of boar taint or castration in the first place. 
Indeed,  when  complaints  regarding  off-smelling  meat  are  received,  it  is  difficult  for 
suppliers to determine whether the presence of boar taint is the cause of the odour.  

There  must  be agreement in the  supply chain for  many of these practices to work. The 
production of boars or vaccinated pigs is not possible unless there is an ultimate market 
into which such meat can be sold. This is especially true for those countries where suspicion 

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towards production without castration is high, and additional effort must be made at the 
farm,  slaughterhouse  and  processing  levels  to  ensure  that  no  tainted  meat  enters  the 
supply chain.  

In  France,  the  Netherlands,  Denmark,  Belgium,  Germany  and  Norway,  additional 
investments have had to be made at slaughterhouse level where boars are slaughtered. 
These investments are practical only where there is a guaranteed market for meat from 
boars or vaccinated pigs. A number of them are practical when a sufficient volume of boars 
are to be processed through the slaughterhouse.  

The practices are all used to different degrees by slaughterhouses that process boars, and 
all require some degree of investment, either in hiring or training personnel or investing in 
additional equipment or infrastructure. Incentives to supply boar meat must be enough to 
allow for additional investment in such processes.  

Investment  in  such  processes  is  also  only  practical  if  farmers  are  raising  boars  or 
vaccinated  pigs.  Many  practices  at  farm  and  at  slaughterhouse  level  benefit  from 
coordination between farm and slaughterhouse. For example, split sex rearing easily allows 
farmers to provide animals to the slaughterhouse in split sex groups or participate in ‘boar 
free’ times on the slaughterline.  

5.5  Description of problems encountered and solutions found   

Several challenges were encountered while researching the elements of best practice. The 
amount of information available varied greatly depending on the point in the supply chain 
under  consideration.  Information  on  practices  at  farm  and  slaughterhouse  level  was 
available through both interviews, documentation and field visits. Information from retail 
and  food  service  was  not  as  accessible  and  the  study  team  encountered  challenges  in 
identifying  practices. Various sources of information were consulted in an effort to address 
these issues (such as different supply chain actors and their representative associations, 
websites of retailers and assurance schemes, and our team of experts).  

The  number  of field  visits  was  comparatively  small.  This  was  due  to  several  factors:  in 
some  instances,  field  visits  were  not  deemed  likely  to  provide  information  beyond  what 
was available from telephone interviews. In other instances, stakeholders were reluctant 
to participate in field visits.  

There was a lack of information on costs and feasibility. This is a common problem with 
this  kind  of  study.  Experts  within  the  study  team,  and  particularly  participants  to  the 
Advisory Board, were able to offer advice on the feasibility of certain practices. Previous 
studies  provided  some  insight  on  costs.  To  address  this  challenge,  all  data  gaps  were 
mapped systematically and this mapping informed the stakeholder consultation. Feedback 
received during the consultation provided additional information on how practical the draft 
elements are from stakeholders’ perspectives.  

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6 

Deliverable 4 (1) – Consultation process  

A  wide  range  of  feedback  was  received  from  stakeholders  during  the  course  of  the 
consultation  process.  Some  of  the  feedback  received  focused  on  the  overall  format  and 
structure  of  the  documents,  finding  that  the  existing  presentation  did  not  provide  the 
necessary detail and did not appropriately address the links between different parts of the 
supply chain.  

On some issues, there were clearly contradictory opinions between stakeholders, some of 
which reflect broader debates on pig welfare. For example, the inclusion of slatted floors 
was  contentious  for  some  stakeholders  and  there  were  very  different  views  on  sex-
separated  rearing  and  its  effectiveness  at  reducing  aggression  among  boars.  More 
generally,  the  document  on  farming  practices  for  entire  males  generated  the  most 
feedback.  

Opinions also seemed to be divided on the efficacy of existing instrumental methods versus 
human nose techniques. For a few stakeholders, human nose techniques are not reliable 
enough for commercial use and there is too great a risk that tainted meat will enter the 
supply  chain.  For  most  stakeholders,  however,  existing  instrumental  methods  are  not 
sufficient and are too costly for commercial use. Indeed, the method currently established 
in  Denmark  has  not  been  implemented  anywhere  else  in  spite  of  many  years  of  use  in 
commercial conditions. Rather, most users of the human nose method saw it as a reliable 
solution for detecting boar taint, until an affordable chemical detection method is found.  

Some comments came from stakeholders who recommended related studies that pointed 
to new or alternative practices. In these instances, no action was taken as only practices 
found in  commercial  conditions  were  included in the  documents. In  some instances, the 
study team followed up with stakeholders to confirm whether the practices described were 
also used commercially.  

Finally, the consultation process highlighted gaps that were then filled by complementary 
research, including additional desk research and interviews. 

A record of all comments received through the online consultation is provided in Annex 5. 
For  each comment, this  includes  ICF’s  response  and  any  actions taken  to  address these 
comments. 

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7 

Deliverable 4 (2) - Final best practices 

This section presents the elements of best practice identified through data collection and 
revised on the basis of the stakeholder consultation and advisory board meeting. Each sub-
section focusses on one of the eight issues listed in the terms of reference for this project 
(see Table 1).  

Boar taint is caused by the skatole and androstenone accumulation in tissues of pigs, 
usually  uncastrated  males.  These  compounds  contribute  both  individually  and  in 
combination to the perception of boar taint. Some of the measures believed to impact boar 
taint  specifically  impact  androstenone  levels,  others  specifically  impact  skatole  levels.  
Practices in this document therefore generally refer to one or the other. 

This  section  considers  practices  observable  at  specific  points  in  the  supply  chain  and 
targeted at a specific type of actor within that chain. However, many of the challenges of 
switching  to  entire  males  or  vaccinated  pigs  relate  to  relationships  and  communication 
between different members of the supply chain. Case studies are presented in this report 
in Section 5 providing examples of transitions that have occurred in three different Member 
States with involvement from different types of actors.  

7.1  Q1. Farmers – uncastrated pigs: management techniques  

This document lists good  practice  examples  for  reducing the  risks of boar taint in entire 
males at farms. These practices are all currently used in commercial operations in the EU.  

Making the transition to  raising  entire males  requires  careful  consideration and planning 
on the part of the farmer. The following guide refers to practices that may be of interest 
to farmers making such a transition. In addition to the practices described, it is important 
for  all  farmers  to  communicate  with  their  supply  chain  and customers  before  and 
during any transition to raising entire males. Understanding the costs and benefits to other 
parts of the supply chain will also help farmers advocate for and lead the transition away 
from surgical castration. 

Things to consider 

è  Producing entire males without boar taint can mean reduced costs and efforts on some 
aspects, and additional expenses on others. In some markets, financial incentives exist 
for  entire  male  production.  The  farmer  should  assess  and  compare  those  costs  and 
benefits. 

è  Not  all  customers  will  accept  boar  meat.  The  farmer  should  make  sure  they  have 

customers for boar meat before moving to the production of entire males. 

Case study: COOPERL’s transition to entire males 

COOPERL is a large pig meat producer in France that integrates farmers, feed producers, 
slaughterhouses and processors. In 2013 COOPERL transitioned towards the production of 
entire males and convinced partners further down the supply chain to transition with them. 
This transition involved several changes to farm level practices. Further details on this case 
study are provided in Section 5.1.1. 

7.1.1  Managing boars - principle 

Farmers  aiming  to  raise  entire  males  need  to  learn  how  to  manage  boars  and  their 
behaviour.  Some  farmers  report  increased  physical  and  sexual  aggressiveness  among 
boars. Keeping these behaviours to a minimum improves welfare and keeps stress levels 
low. 

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Many of the practices included in this document, including practices to reduce competition 
at feeding and keeping good housing conditions, can help minimise aggressive behaviour 
among boars.  

Boars  require  consistent  handling  as  well.  They  are  particularly  sensitive  to  changes  in 
management. A regular routine, including their feeding, climate and housing situation, can 
help reduce stress in boars.  

Further reading 

For  additional  information  on  handling  boars,  see  existing  guidance  produced  by 
Wageningen  University. 
tips  and 
recommendations’. 
https://www.boarsontheway.com/wp-
Available 
content/uploads/2018/08/Flyer-Berengedrag-v4-engels-2.pdf  

‘Reducing  mounting  behaviour  of  boars  – 

at: 

7.1.2  Flooring and Housing 

By  improving  the  overall  quality  of  flooring,  housing  and  pig  management,  stress  and 
fighting may  be  reduced.  This is  good  for  welfare  and  reducing  boar taint,  as  increased 
stress has been associated with higher levels of taint. Clean and dry environments are also 
important to prevent boar taint.  

7.1.2.1  Keeping pigs clean and dry 

Keeping pigs clean may help reduce skatole levels.  

Pens should be cleaned regularly. 

Where straw is used for bedding, it should be kept as clean as possible and topped up or 
refreshed regularly.  

Fully or partially slatted floors are also used to help keep pig environments clean and dry. 
They  help  to  eliminate  urine  and  faeces  from  pens.  Fully  slatted  floors  may  lead  to 
increased  lameness  and  injuries,  however.  Some  Member  States  (including  the 
Netherlands, Denmark, Finland and Sweden) have prohibited or restricted the use of fully 
slatted floors.  

Advantages 

è  Dry floors keep pigs clean and improve overall hygiene. 

Disadvantages 

è  Fully slatted floors may lead to other welfare issues. 

Things to consider 

è  Floors should be well-maintained. For example, if slatted floors are used, the edges can 

become sharp and this can increase the risk of injuries.  

è  Keeping floors dry is dependent on good ventilation.   

7.1.2.2  Sex-separated rearing 

Separating  boars  and  gilts  means  they  will  not  smell  or  hear  one  another.  The  sight  or 
smell of gilts may increase the levels of hormones linked with boar taint. Raising boars in 
sex-separated groups may also help reduce aggression, although the evidence on this is 
not clear. For pigs raised to heavier weights and older ages, separating by sex is necessary 
to prevent the risk of sow pregnancy.  

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Separation  makes  some  of  the  feed  options  for  reducing  boar  taint  more  practical  and 
economical. When  boars  and  gilts  are  separated,  the  more  expensive  feeds  (with  taint-
reducing additives) can be provided to boars only.    

Separating  pigs  by  sex is  done  at  weaning, the  start of the finishing  phase or  when the 
pigs reach a certain weight. Boars and gilts may be separated either by pen, in different 
areas of a shed or in different sheds altogether.  

Many  slaughterhouses  require  farmers  to  provide  pigs  in  sex-separated  groups.  Sex-
separated rearing allows farmers to do this without separating groups when they are taken 
to slaughter. 

Advantages 

è  Separation at rearing stage reduces logistical requirements when slaughterhouses 

request sex-separated groups. 

Disadvantages 

è  Separation may lead to increased aggression among boars. 

Things to consider 

Sex-separated  rearing  may  require  additional  infrastructure.  Separate  pens  need  to  be 
available. If separate feed will be provided to boars and gilts, farmers will need separate 
feed silos.  

7.1.2.3  Wean to finish grouping 

Pigs are kept together in their litter groups (which means with their siblings). There is no 
or  minimal  mixing  after  weaning.  These  groups  are  also  sent  to  the  slaughterhouse 
together. This reduces stress and may therefore contribute to a reduced instance of boar 
taint.  

Wean to finish grouping might also be combined with sex-separated rearing. This would, 
however, require smaller finisher pens for groups of around 4-5 animals.  

Advantages 

è  This reduces stress in pigs throughout life. 

è  This may contribute to increased weight gain. 

è  This can also help prevent the spread of disease and contribute to animal health.  

Things to consider 

è  This implies additional logistics to separate animals before slaughter, if slaughterhouses 

request sex-separated groups. 

è  Smaller pens may lead to additional housing costs. Separate pens need to be available 

to ensure groups can stay together.  

7.1.2.4  Low stress environments 

Some good practices for reducing stress are: 

  Make  sure  pigs  have  enough  space.  Legal  requirements  differ  depending  on  pig 
weight: for example, at least 0.65 m2 per pig for pigs between 85 and 110 kg; at 
least 1 m2 for pigs above 110 kg. Pig pens should enable pigs to comfortably rest, 
eat and eliminate.  

  Keep group sizes small. Keeping groups to around 30 pigs or less can reduce stress, 

competition and improve welfare. 

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  Remove ill or injured pigs from the pen.  
  Use partly open pen walls. This allows pigs to have contact with neighbouring pens 

and can help reduce aggressive behaviour.    

  Ensure temperature control and proper ventilation. Keep temperatures as consistent 

as possible. Make sure housing is properly insulated and avoid draughts.  

  Ensure suitable lighting, including a consistent day and night rhythm. Avoid overly 

bright lights. 

  Keep pigs supplied with sufficient fresh water. 
  Provide  enrichment,  such  as:  wood  and  branches,  straw  in  racks  or  as  bedding, 
alfalfa  and  hemp  rope.  Enrichment  objects  that  are  destructible,  edible  and 
encourage  rooting  are  most  effective.  Enough  enrichment  materials  should  be 
provided so that pigs do not need to compete with one other. This helps keep boars 
calm and occupied.  

Advantages 

è  Low stress environments improve overall pig welfare. 

è  They also reduce adverse behaviours such as aggression, ear- and tail biting. 

Disadvantages 

è  Implementing these practices may increase costs. 

è  If straw is used, it must be kept dry.  

Things to consider 

There is existing guidance on improving the welfare of pigs. Many assurance schemes and 
certification programmes have their own welfare standards and requirements. These can 
help farmers decide how to change their practices.  

Further reading 

Previous  European  Commission  work  on  better  welfare  conditions  to  reduce  tail  biting 
contains  good  guidance  on  reducing  stress  in  pig  environments.  See:  European 
Commission 
at: 
Available 
https://ec.europa.eu/food/sites/food/files/animals/docs/aw_practice_farm_pigs_tail-
docking_eng.pdf  

tail-docking. 

Cutting 

(2016) 

need 

the 

for 

7.1.3  Reducing competition at feeding 

Reducing competition at feeding can reduce stress, improve welfare and can help reduce 
the risk of boar taint.  

Feed  for  boars  should  not  be  restricted  and  instead,  boars  should  be  fed  on  demand. 
Feeding  systems  with  multiple  feeding  spaces  help  to  reduce  competition.  For  example, 
offering feed in long troughs can help to reduce competition. Troughs should be at least 
17 centimetres (cm) long per piglet, and at least 22 cm long per growing pig. 

One option for reducing competition at feeding is “wet feeding”, or “liquid feeding”. Wet 
feed consists of a mix of dry feed and water (or other liquids). With this system, pigs drink 
their feed rather than chewing it. Wet feeding is used largely for controlling consumption. 
A long trough is used, allowing all pigs to eat at the same time. Alternatively, a sensor-
managed system is used with smaller troughs. This schedules feedings and avoids "rush 
hour"  effects.  Wet  feeding  systems  allow  for  better  control  over  feed  conversion.  They 
make it easier to calculate correct feeding amounts.  

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Farmers who use wet feeding should ensure that pigs also have access to sufficient fresh 
water.  

Advantages 

è  In  addition  to  reducing  boar  taint,  this  practice  has  positive  effects  on  animal 

welfare and pigs’ growth. 

Disadvantages 

è  The need to install feeding equipment means that a transition to this practice has a 

high upfront cost. 

Things to consider 

è  Pens should be large enough to accommodate additional feeders or feeding equipment. 
Pigs  should  still  have  enough  space  to  keep  separate  areas  for  resting,  activity  and 
elimination. 

è  Additional  feeders  may  disrupt  the  air  flow  through  a  pen.  Check  that  ventilation 

systems are functioning when making any changes to infrastructure.  

7.1.4  Breeding 

Selective  breeding  can  be  used to  help  reduce androstenone  levels. There  are  two  main 
breeding techniques used.  

The first method is to select on breed. Certain breeds of boars, such as the Piétrain, are 
less likely to have boar taint.   

The  second method  selects within  a  breed. Several  breeding  companies have developed 
techniques  and  practices  that  allow  them  to  offer  ‘low-taint’  sperm.  Topigs  Norsvin  has 
developed  a  method  to  select  low-taint  boars.  Their  low-taint  sperm  is  available  for 
purchase.  Similarly,  Nucleus  in  France  offers  Piétrain  selected  low-taint  reproducers, 
labelled  “INO”.  A  low-taint  line  has  also  been  developed  by  the  University  of  Bonn  in 
Germany,  in  partnership  with  the  breeding  company  GFS  and  the  slaughterhouse 
Westfleisch.  The  retailer  Delhaize  in  Belgium has  worked  with  breeding  company  PIC  to 
develop a low-taint line for a castration-free pork label. 

Advantages 

è  Selective breeding reduces boar taint risk from the outset. 

Disadvantages 

è  Dosages of low-risk sperm are sometimes priced higher than normal dosages. One 
dosage of Nador sperm from Topigs Norsvin costs an additional €1 more per dosage. 
By contrast, Nucleus’ INO boars are available at no premium cost compared to other 
boars. 

è  Availability of these products varies per country. 

Things to consider 

è  Switching to a different breed of pig depends on the customers or market involved and 
should  be  discussed  within  the  supply  chain.  Switching  breeds  may  also  require 
changes to farm management practices. 

è  Using  ‘low-taint’  sperm  only  addresses  one  half  of  the  genetic  material  of  pigs.  The 

potential contribution of the genetic material of sows should also be considered.  

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7.1.5  Feed composition 

A range of additives can be used in pig feed to lower skatole levels. Changes to feed can 
also be used to improve growth rates, lowering the age at slaughter and reducing the risk 
for boar taint.  

Things to consider 

è  Farmers who invest efforts in feed composition to reduce boar taint tend to feed boars 
and  gilts  separately.  Feed  composition  solutions  are  therefore  best  suited  for  sex-
separated rearing.  

è  Farmers need separate feed bins or silos to store different types of feed for different 

categories of animals. 

è  Farmers  may  wish  to  make  other  changes  to  feed  composition  when  raising  entire 
males. For example, boars tend to be leaner than gilts and castrates. This can cause 
problems  for  processors  and  they  may  request  or  incentivise  changes  to  feed 
composition that increase the fat content in boars.  

è  Farmers considering  any  changes  to  the  composition of  feed  should  also  ensure that 

pigs continue to enjoy their food and that it meets their taste expectations.  

7.1.5.1  Chicory root (cichorium intybus) 

Inulin,  a  dietary  fibre  most  commonly  extracted  from  chicory  root, significantly  reduces 
the level of skatole – responsible for boar taint – in boars. Most animal feed suppliers sell 
dried chicory root. It is included in feed (at 7% - 15%) two to three weeks before slaughter. 
There is evidence that 3 to 4 days before slaughter may be sufficient to produce the desired 
effects, however. Jerusalem artichoke is another source of inulin.  

For example, a Dutch farmer found that among pigs fed with inulin, 52% fewer presented 
boar taint compared to pigs fed a standard diet. The diet decreased skatole levels in pig 
carcasses by 80% on average. Inulin made up 7% of the animal’s diet and was given for 
three weeks before slaughter. 

Advantages 

è  This method has been proven to successfully reduce skatole and boar taint. 

è  Pigs fed with this diet may grow faster than other pigs.  

è  This diet has positive effects on pig behaviour, as it results in reduced biting and 

jumping. This may in turn reduce the risk of injuries.  

Disadvantages 

è  This feeding practice has a high cost. 100kg of inulin costs around €200. A cheaper 

option using beet pulp as an additional ingredient is also available. 

Things to consider 

è  Chicory may not be available from all feed suppliers and may need to be sought out 

separately.  

è  Silo  management  is  important  for  farmers  who  wish  to  use  feed  additives  such  as 

chicory root.  

è  For some farmers, it may also be possible to plant chicory on farm.   

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7.1.5.2  Diet with adjusted amino acids 

Boars  can  be  fed  a  diet  with  increased  lysine.  Lysine  is  an  essential  amino  acid  and 
important for pig nutrition. It accelerates growth in the finishing phase. This reduces the 
number of slow-growing pigs and can help slow-growing pigs reach their slaughter weight 
at a younger age. This helps reduce the risk of boar taint. 

Adjusting amino acids can be discussed with feed suppliers or alternatively, lysine can be 
purchased as a supplement.       

Advantages 

è  This diet increases growth rate at finishing stage. 

è  A diet high in amino acids may help reduce sexual and aggressive behaviour.  

è  Supplementing with amino acids can help reduce variation in slaughter weights.  

Disadvantages 

è  This diet may add cost compared to conventional diets. 

Things to consider 

Farmers  may  wish  to  find  a  feed  supplier  that  provides  custom-made  nutrition,  so  that 
amino acids can be adjusted to fit the farm’s needs. 

7.1.5.3  Protein reduced diet prior to slaughter 

Some feeds that are typically given to pigs, such as soybean-based feeds, have a higher 
protein content than other feeds, such as cereals. Switching to a low-protein, grain-based 
diet prior to slaughter reduces skatole levels and the risk of boar taint.  

A protein-reduced diet may contain, for example, 48% wheat and 48% barley. These diets 
must also contain the correct level of essential amino acids.     

Boars should be given a protein reduced diet at least four days before slaughter for this 
to take effect.    

Advantages 

è  This diet has a low cost. 

Things to consider 

Providing  a  grain-based  diet  prior  to  slaughter  can  be  done  alongside  other  feeding 
practices, including providing diets with adjusted amino acids. Diets with adjusted amino 
acids are provided throughout the finishing phase to improve growth. The switch to a low-
protein diet only needs to occur four days before slaughter.   

7.1.5.4  Commercial feed designed to reduce boar taint 

There  are  currently  two  examples  of  feed  products  on  the  market  that  are  specifically 
intended to reduce boar taint. These feeds are given to boars in the last few weeks before 
slaughter. They combine fibres and feed additives to reduce skatole levels.  

These  feeds  are  available  from  Dumoulin  in  Belgium  (Taintstop)  and  Vitelia  in  the 
Netherlands. 

Advantages 

è  This feed combines several evidence-based feeding techniques. 

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Things to consider 

These  feeds  cost  significantly  more  than  standard  feed  but  only  need  to  be  provided 
between  one  to  two  weeks  before  slaughter  to  take  effect.  In  Belgium,  for  example, 
Taintstop costs around 100 EUR per tonne more than normal feed and should be given to 
pigs two weeks before slaughter.  

7.1.6  Scheduling slaughter at a young age 

Farmers may decide to slaughter entire males when they reach a certain age or weight, 
which usually differs from the slaughter weights of other pigs (such as castrated pigs).  

Although  slaughtering  at  a low  weight is  often cited  as  a  way to  reduce  the  risk of  boar 
taint,  age  is  the  more  important  factor.  Younger  pigs  may  not  have  developed  the 
characteristics related to boar taint, such as sexual behaviour and aggressiveness. Besides, 
using  weight  as  a  proxy for  age  means slaughtering  slow-growers  at  a  later  age,  which 
entails  a high  risk  for  boar taint.  For this  reason,  farmers  may  choose to  slaughter  pigs 
before a certain age.  

In some cases, good farming practices make it possible to increase weight while reducing 
the proportion of tainted carcasses.  

In a German slaughterhouse, slaughter weight has been increased from 90-92 kg to 95 kg 
dead  weight  as  a  result  of  improvements  in  feeding  schedules,  genetics  and  pig 
management. Following these changes, the proportion of tainted carcasses decreased from 
5-8% to 2-2.5%. 

Farmers can therefore use feedback from slaughterhouses to identify trends related to boar 
taint and choose the appropriate age of slaughter. For example, farmers may decrease the 
age  threshold  if  slaughterhouses  report  a  high  number  of  tainted  carcasses  for  pigs 
slaughtered after a certain age.  

Age  can  be  monitored  through  markers  on  the  pigs,  such  as  ear  tags.  Wean-to-finish 
grouping can also be used to keep pigs of the same age together. Reducing competition at 
feeding could be used to help reduce the discrepancy between growth rates.  

Advantages 

è  This practice is easy to implement. 

Disadvantages 

è  Farmers may receive a lower price per pig, as younger pigs tend to weigh less than 
older  ones.  In  the  absence  of  a  financial  incentive,  farmers  may  decide  not  to 
implement this practice 

è  This practice may not be feasible in countries where pigs are slaughtered at high 

weights. 

Things to consider 

There may be specific customer requirements around the weight ranges of pigs that make 
selection  for  slaughter  at  a  certain  age  difficult.  As  with  other  changes,  it  is  therefore 
important to discuss this possibility with customers before and during the transition.  

7.2  Q2. Farmers – vaccinated pigs: vaccination process 

This document provides good practice examples that can be used by business operators to 
successfully  use  vaccination  against  boar  taint.  These  practices  are  used  in  commercial 

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operations. This document  also  discusses some  of the  advantages  and  disadvantages of 
these practices. This will help you to choose what practice suits you best. 

Making the transition to raising vaccinated pigs requires careful consideration and planning 
on the part of the farmer. The following guide refers to practices that may be of interest 
to farmers making such a transition. In addition to the practices described, it is important 
for  all  farmers  to  communicate  with  their  supply  chain  and customers  before  and 
during  any  transition  to  vaccination  against  boar  taint.  Understanding  the  costs  and 
benefits to other parts of the supply chain will also help farmers advocate for and lead the 
transition away from surgical castration. 

7.2.1  Vaccination principle 

Vaccination  against  boar  taint  is  as  an  alternative  to  physical  castration  to  control  boar 
taint. Pigs are injected with a vaccine that stimulates their immune system and blocks the 
production of the substance responsible for the onset of boar taint (called Gonadotropin-
Releasing Factor - GnRF). Vaccination against boar taint is performed using Improvac®, a 
vaccine marketed by Zoetis Animal Health. A similar vaccine, Ceva Valora®, is marketed 
by Ceva Animal Health, but this vaccine is not yet commercially available in Europe.   

Meat from vaccinated pigs can be safely eaten at any time after the vaccination.  

Farmers have used vaccination against boar taint in Belgium and Poland to produce fresh 
meat since 2010. 

Belgian farmers are paid 0.01€/kg more for vaccinated pigs than for castrated pigs. 

One dose of Improvac costs between €1.40 and €1.5051.  

Things to consider 

è  It is important that farmers inform slaughterhouses about their use of vaccination, the 
characteristics of the vaccine and its effects on pigs and meat. Providing information 
about what controls are performed to ensure that the vaccine is administered correctly 
helps build trust in the supply chain. 

è  The  costs  of  vaccination  is  compensated  by  the  improved  feed  efficiency  of  pigs. 

Additionally, pork buyers may pay a premium for meat from vaccinated pigs.   

7.2.2  Vaccination procedure 

The vaccine may be administered by farmers, or by others (such as external vaccinators 
trained and certified by vaccine suppliers, depending on the preferences and commercial 
arrangements  of  each  farm).  European  authorities  require  vaccine  administrators  to  be 
trained and certified.  

The  same  procedure,  as  prescribed  by  the  manufacturer,  should  be  applied  for  both 
injections. The vaccine is injected under the skin behind the pig’s ear (see picture below: 
the red mark indicates the correct site where the vaccine should be injected). As for other 
injections  given  to  pigs,  it  is  important  that  the  vaccination  site  is  clean  and  dry.  Any 
drippers and sprays should therefore be turned off well before vaccination. 

The  person administering  the  vaccine should calmly  enter the  animal’s  pen.  There is  no 
need to restrain pigs individually, and they can be vaccinated in their pens. Tools such as 
handling boards can be used to gently move animals and bring them close to each other, 
so that  they  can  be  easily  vaccinated. Vaccination  should only  start  when  pigs  are  calm 

51 This is the standard price paid by farmers. This price may decrease when the vaccine is sold in high volumes. In 

addition to purchasing the vaccine, farmers may also decide to pay for additional veterinary services offered by 
vaccine suppliers.  

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and grouped  together on one side of the pen so that they  can easily  be reached  by the 
vaccinator.  It  is  important  that  all  doses  of  the  vaccine  are  administered  correctly  by 
trained staff to avoid risks of stress and abscesses. 

Each  pig should  be marked  immediately  after  vaccination  (for  example,  with  a  coloured 
marker), to distinguish it from pigs which still have to receive their dose. To avoid possible 
mistakes, pigs should never be marked before they are vaccinated. In case of doubt as to 
whether  a  pig  has  successfully  received  its  dose,  the  pig  should  be  revaccinated 
immediately. 

Figure 3.  Recommended site for the injection of the vaccine52 

The  person  administering  the  vaccine  should  have  been  trained  on  all  aspects  of  the 
vaccination process: 

•  The preparation, maintenance and cleaning of the vaccination syringe; 

•  The administration of the vaccine and the handling of pigs; and 

•  The preparation of control documents53. 

This training is usually delivered by Zoetis free of charge. It may take half a day to one 
day for a farmer to be trained and evaluated on all aspects of the vaccination process.  

Advantages 

è  The process of administering the vaccine is similar to that for other vaccines.  

è  Vaccination has a very high success rate when applied correctly. 

Disadvantages 

è  The  vaccination  requires  additional  effort  from  the  farmer.  However,  if  a  farmer 
switches from  physical  castration to vaccination,  this  additional effort is offset  by 
the reduced workload from not having to physically castrate the pigs.  

52 Image drawn from original material provided by Zoetis Inc. Source: Zoetis (n.d.) Implementation on-farm. Training 
program for the implementation of Improvac – Vaccine for the control of boar taint (unpublished). Produced with 
permission from Zoetis Inc. (July 2018). 

53  See also document titled: “Farmers - immunocastrated pigs: provide assurance to slaughterhouses that 

immunocastrated pigs do no present detectable boar taint”. 

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è  The  vaccination  procedure  is  harder  to  perform  on  pigs  housed  outdoor  than  on 
those  raised  indoor.  Outdoor-raised  pigs  need  to  be  herded  into  a  shoot  or  pen 
before the vaccine is administered. 

Things to consider 

The staff administering the vaccine needs to be properly trained to ensure that the vaccine 
is  administered  correctly.  Staff  also  need  sufficient  time  to  become  familiar  with  the 
vaccination tools (see section 2 of this document).   

7.2.3  Dosing gun 

The vaccine can have the same effects in humans as in pigs. For this reason, it is necessary 
to avoid the risk of accidental self-injection. People who accidentally self-inject the vaccine 
should not use the vaccine anymore.    

A special syringe (also called dosing gun – see picture below) should be used to administer 
the vaccine.  This tool has several  safety mechanisms: the needle  is  protected,  and  it  is 
only activated once the gun is pressed against the pig's body and the trigger is pulled.  

The  dosing  guns  recommended  by  vaccine  suppliers  are  Secure  Plus  by  NJ  Phillips  and 
Sekurus by Simcro. Zoetis provides dosing guns to farmers for free.  

To avoid the risk of self-injection, the person administering the vaccine should always make 
sure to point the gun away from his/her body. If the gun is not pointed away, there is a 
risk  that  the  person  can  inject  his/her  own  leg  if  the  pig  moves  during  the  vaccination 
process. 

Figure 4.  Example of a dosing gun for the injection of the vaccine54 

Advantages 

è  The gun has a safety mechanism to avoid self-injection of the vaccine 

è  The gun is easy to use and is frequently supplied for free by vaccine distributors 

è  It is appropriate for use with both small and large pigs 

54 Image drawn from original material provided by Zoetis Inc. Source: Zoetis (n.d.) Implementation on-farm. Training 
program for the implementation of Improvac – Vaccine for the control of boar taint (unpublished). Produced with 
permission from Zoetis Inc. (July 2018). 

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Disadvantages 

è  Staff need to be trained to use the dosing gun and keep it clean 

Things to consider 

è  The correct handling of the injection gun requires training to ensure safety. 

è  The dosing gun and needles require cleaning and maintenance, consistently with the 

requirements specified by manufacturers of these tools.  

7.2.4  Protective clothing 

Leather  protective leggings or chaps may  be used to  protect the  lower  leg  and  create  a 
barrier to prevent self-injection. 

Advantages 

è  This is relatively low cost  

Disadvantages 

è  Protective clothing may cause discomfort in hot weather 

7.2.5  Vaccination schedule 

The vaccination schedule is set as per the recommendations of the manufacturer. However, 
within the recommendations provided by suppliers, vaccination schedules are flexible and 
can  be  adjusted  according  to  the  desired  outcome  parameters  of  carcass  weight,  feed 
conversion ratio, and fat content.  

Things to consider 

è  Implementing the recommended schedule requires thorough record-keeping of the age 

of each pig on farm and additional planning. 

è  Adjustments to the normal schedule require trials ran jointly with slaughterhouses and 

processors. 

7.2.6  Main protocol 

The main protocol for vaccination requires the injection of two doses. The first injection is 
done at no earlier than eight weeks of age and has no physiological effects. The second 
should  be  given  at  least  four  weeks  after  the  first  and  within  four  to  six  weeks 
before  slaughter.  This  is  based  on  recommendations  from  the  manufacturer.  The 
European licence, however, allows pigs to be sent to slaughter without risk for boar taint 
up to the tenth week after the second vaccination.  

The  effects of  the vaccine  are  temporary  and  reversible.  The substances  responsible  for 
boar  taint  (mostly  androstenone  and  skatole)  decrease  significantly  two  to  three  weeks 
after the second dose and these effects last until approximately 10 weeks after the second 
dose.  

An additional injection might be applied if the intended effect is not observed (for example, 
if the pig behaves as an entire male55).  This situation is relatively rare. When farmers are 

55 For additional information on the checks to verify if vaccination has been successful, see document titled: 

“Techniques and best practices to provide assurance to slaughterhouses that immunocastrated pigs do no present 
detectable boar taint”). 

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well experienced with the use of the vaccine and receive regular training on vaccination, 
the proportion of pigs requiring a third dose may be as low as 0.3% of pigs. 

A generic vaccination timeline, as recommended by the manufacturer, is presented below.  

Figure 5.  Generic timeline to administer the vaccine56 

Farmers may adapt the timeline according to their needs (for example, based on specific 
characteristics of their production process, or according to slaughterhouses’ requirements 
on market weights). 

If  piglets  have  to  be  transported  long  distances  between  the  nursery  house  and  the 
fattening site, it is better to let them rest for a week and reduce their stress levels before 
administering the first dose.  

Farmers may align vaccination timings across different pig batches. For example, they can 
ensure that the second vaccination of an older batch is made on the same day of the first 
vaccination of a younger batch. This can make the vaccination process more efficient. 

Pigs need to be slaughtered at the latest 10 weeks after the second vaccination; a third 
dose may be given to heavy or older pigs (see also section titled “Use of three injections 
for larger pigs”).  

7.2.7  Early vaccination 

Some farmers choose to apply the second vaccination as early as possible. That is to reduce 
aggressiveness towards other pigs. Reduced aggressive behaviour is observed from one to 
two  weeks  after  the  administration  of  the  second  dose.  Pigs  reach  puberty  on  average 
around 16-18 weeks of age and will increasingly show aggressive behaviour when growing 
older. For example, if the vaccination timeline is set to apply the second vaccination at 19 
weeks, with slaughter at 24-25 weeks age, but the pigs show excessive sexual behaviour 
around  19  weeks, then  the  second  vaccination  could  be  given  one  to  two  weeks  earlier 
(that is, at week 17) without a need to change the slaughter time. 

The commercially available vaccine is not licensed for use in pigs younger than 8 weeks, 
and  the  second  dose  should  be  administered  at  least  four  weeks  after  the  first  one.  So 
there is a limit on the recommended minimum age of vaccination. 

Advantages 

è  Early vaccination minimises undesirable pig behaviour, such as aggressiveness. This 
is beneficial to animal welfare and may also improve carcass quality (for example, 
by reducing the risk of skin lesions and leg damages). 

è  Another reason to vaccinate pigs early is to maximize the amount of intramuscular 

fat and backfat. Some markets require pork products with higher fat levels. 

56 Image drawn from original material provided by Zoetis Inc. Source: Zoetis (n.d.) Implementation on-farm. Training 
program for the implementation of Improvac – Vaccine for the control of boar taint (unpublished). Produced with 
permission from Zoetis Inc. (July 2018). 

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Disadvantages 

è  The  time  between  the  second  dose  of  the  vaccine  and  the  slaughter  should  not 
exceed 10 weeks; if this happens, a third dose of the vaccine should be applied 4 
to  10  weeks  before slaughter  to ensure  absence  of  boar taint  in carcasses. Early 
vaccination  may  therefore  require  the  administration  of  a  third  injection.  For 
example:  first  vaccination  at  week  8;  second  vaccination  at  week  12;  third 
vaccination at week 18 to 20; slaughter at week 24. 

Things to consider 

The correct vaccination schedule needs to be aligned with husbandry practices on the farm. 
It needs to be adjusted to the market requirements set by the slaughterhouse as well.  

Case study: vaccination protocol applied by a Polish farm 

A Polish farm using Improvac has had success slaughtering animals at a later point, around 
8-9  weeks  after  the  second  vaccination.  They  have  found  that  this  maximises  their 
economic returns. Further details on this case study are provided in Section 5.1.2. 

7.2.8  Late vaccination 

Some farmers choose to administer the second dose as late as possible.  

Advantages 

è  Farmers choose to vaccinate late to maximise the ‘boar-like’ performance of pigs, 

and therefore achieve better feed conversion and leaner carcasses.  

Disadvantages 

è  Due  to  late  vaccination,  pigs  may  become  aggressive  because  of  increased 
testosterone levels. This can be avoided by giving pigs more space or through other 
management  techniques.  Alternatively,  earlier  second  vaccination  should  be 
considered.  

7.2.9  Use of three injections for larger pigs 

A third dose may be administered to heavy or older pigs before slaughter. The third dose 
can be given 10 weeks after the second dose. For example, if the pig is scheduled to be 
slaughtered at 28 to 32 weeks of age, then the third dose can be given at 24 weeks of age.  

Pigs  tend  to  be  slaughtered  at  heavy  weights  for  commercial  reasons  (such  as  market 
requirements  by  slaughterhouses  and  processors),  rather  than  due  to  considerations 
associated with the use of the vaccine. 

A protocol with 3 injections has been used in Spain and Italy to produce both fresh meat 
and meat destined for dry curing. 

Case study: Vaccination protocol to produce cured hams in Spain 

In  Spain,  farmers  vaccinate  Iberian  pigs  against  boar  taint  to  produce  cured  hams. 
Vaccination  has  been  successful  in  improving  profitability  and  animal  welfare  while 
maintaining high product quality. Further details on the Spanish experience are provided 
in Section 5.1.2. 

Advantages 

è  This practice helps avoid boar taint in pigs which are slaughtered at heavy weights 

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Disadvantages 

è  If the vaccination is not properly executed, there may be additional stress and risk 

of abscesses associated with the additional vaccination 

Things to consider 

The correct vaccination schedule needs to be aligned with the husbandry practices on the 
specific farms and the market requirements set by the slaughterhouse, processor, or other 
standards. 

7.2.10  Feeding of vaccinated pigs 

Before the second dose of the vaccine, pigs are fed the same way as entire males. After 
the  second  dose,  pigs  tend  to  eat  more  feed  and  gain  weight  faster  than  entire  males. 
Following the second dose, vaccinated pigs also have lower lysine requirements than entire 
males. For this reason, their diet should be adapted and the daily amount of feed should 
be increased.  

For example, the average quantity of feed eaten daily by common breeds of pigs  may be 
increased  by  20%  after  the  second  dose.  On  a  daily  basis, this  results  in  a  weight  gain 
approximately 5% higher than entire males. 

Farmers in Belgium, Poland and Spain have had positive experiences with the better feed 
conversion ratios of vaccinated pigs. The improvement in feed conversion reduces costs. 
This helps compensate for the additional costs of vaccination. 

Advantages 

è  Vaccinated pigs grow faster and reach their slaughtering weight earlier than entire 
males.  Overall,  feed  efficiency  therefore  remains  unchanged  and  due  to  reduced 
lysine requirements, feed costs may be lower. 

Things to consider 

This  practice  may  require  split  sex  rearing  to  offer  optimized  feed  formulations  to  both 
genders. 

7.3  Q3.  Farmers  –  vaccinated  pigs:  provide  assurance 

to 
slaughterhouses that vaccinated pigs do not present detectable boar 
taint 

This document provides good practice examples that can be used by farmers to reassure 
slaughterhouses that vaccinated pigs do not present detectable boar taint. The practices 
mentioned are all currently used in commercial operations in the EU. 

Making the transition to raising vaccinated pigs requires careful consideration and 
planning on the part of the farmer. The following guide refers to practices that may be of 
interest to farmers making such a transition. In addition to the practices described, it is 
important for all farmers to communicate with their supply chain and customers 
before and during any transition to vaccination against boar taint. Understanding the 
costs and benefits to other parts of the supply chain will also help farmers advocate for 
and lead the transition away from surgical castration. 

7.3.1  On-farm checks of pig behaviour 

On-farm  checks  are  one  of  the  ways  that  farmers  have  collected  information  they  then 
sent to slaughterhouses for quality assurance purposes. 

To verify if pigs have been successfully vaccinated, farmers may check their behaviour.  

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These checks are done 2 to 3 weeks after the second vaccination. Checks can be done 
at any time of the day. However, feeding time or the hottest times of the day should be 
avoided. Since pigs’ activity is reduced during these times, it is more difficult to make pigs 
stand to observe them and assess their behaviour. 

Farmers  can  check  pigs’  behaviour  to  verify  whether  they  have  been  successfully 
vaccinated.  Absence  of  sexual  behaviour  suggests  that  vaccination  has  been  done 
correctly. The following characteristics should be absent: 

è  Frequently repeated attempts to mount or penetrate other pigs in the pen;  

è  Enlarged and reddened testicles; and 

è  Repeated aggressive behaviour. 

Presence of one or more of these signs indicates that the pig may have missed a dose.  

Checks for behavioural indicators involve two main steps.  

Firstly, the person performing the checks should enter the farm and inspect all pens from 
the outside, by calmly walking through the building several times. For a building with 500 
pigs, this takes approximately 15-20 minutes.  

Secondly, it is important to have a stop at each pen and check possible signs of repeated 
sexual behaviour. Pens may be observed from the outside, by slowly walking through the 
corridors  between  pens  and  spending  a  few  minutes  observing  each  pen.  Alternatively, 
farmers  may  calmly  enter  the  pens  and  spend  10-15  minutes  in  each  pen  to  observe 
animals.  After 10-15 minutes,  pigs  get used to  the  presence of the  farmer  and  most of 
them have a calm and normal behaviour. At this point, it will be easy to identify pigs which 
show repeated aggressive or sexual behaviour.  

Based  on  these  checks,  suspect  animals  are  marked  and  vaccinated  again.  After  this 
additional dose, some animals may still present signs that suggest a risk of boar taint, such 
as sexual behaviour. In these cases, the slaughterhouse should be made aware that the 
carcass needs to be assessed for possible presence of boar taint.  

Zoetis  trains  farmers  to  conduct  these  checks  in  all  countries  where  they  market  the 
vaccine. Zoetis may also arrange for trained vaccinators to conduct these checks based on 
contractual agreements with farmers.   

Case study: vaccination protocol applied by a Polish farm 

A Polish farm using Improvac has had success slaughtering animals at a later point, around 
8-9  weeks  after  the  second  vaccination.  They  use  behavioural  checks  as  part  of  their 
protocol  for  ensuring  that  all  pigs  are  properly  vaccinated.  Further  details  on  this  case 
study are provided in Section 5.1.2. 

Advantages 

è  It  takes  relatively  little  time  to  perform  checks.  In  most  situations,  behavioural 
indicators are clear: when one or more animals have missed a dose, there is much 
more  agitation  in  the  pen.  Once  farmers  gain  enough  experience  to  understand 
these signals, checks become part of their daily routine. 

Disadvantages 

è  This requires trained personnel to perform checks. Training on conducting on-farm 
checks is delivered by vaccine suppliers together with training on other aspects of 
the vaccination process57.   

57 See also document titled: “Farmers – immunocastrated pigs: vaccination”. 

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è  Sexual  behaviour  may  sometimes  be  confused  with  dominance  behaviour:  to 
establish a hierarchy in a group, for example, some pigs may try to mount other 
pigs.  Dominance  mounting  is  shorter  and  less  frequent  than  sexual  mounting. 
Dominance  behaviour  does  not  necessarily  indicate  that  the  pig  has  not  been 
correctly  vaccinated.  If  trained  to  recognise  these  behaviours,  the  person 
performing the checks will be able to easily differentiate between sexual behaviour 
and dominance behaviour. 

7.3.2  Supply chain assurance 

Farmers may provide information to slaughterhouses to demonstrate that they apply the 
correct  vaccination  procedures  and  checks.  This  helps  reassuring  slaughterhouses  that 
farmers  are  committed  to  providing  high  quality  animals,  and  that  the  risk  of  tainted 
carcasses is low.  

7.3.2.1  Documentation 

Farmers may include information on the quality assurance of the vaccination process58 in 
their  standard  pig  transport  documentation,  to  share  with  slaughterhouses.  Standard 
information would include, for example, the name of the producer, the number of pigs sent 
to the slaughterhouse, their sex, the loading time and vehicle number. Farmers may add 
the following details on vaccination: 

è  The number of vaccinated males; and 

è  A confirmation that vaccinated pigs have been checked prior to slaughter, and that 
farmers have identified pigs which are suspected to present boar taint (if any). 

58 Information on the medicinal products used on a farm is also documented in official medical records. These records, 
however, would not contain information about the results of the on-farm checks carried out to assess the correct 
administration of the vaccine. 

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Figure 6.  Example of a template for sharing information on vaccination with 

slaughterhouses59  

59 Zoetis (n.d.) Implementation on-farm. Training program for the implementation of Improvac – Vaccine for the 

control of boar taint (unpublished) 

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Farmers  may  wish  to  share  with  slaughterhouses  an  additional  document  (vaccination 
declaration), with details on the vaccination process: 

è  The name of the person who administered the vaccine. 

è  The dates of vaccination and the number of animals vaccinated. 

è  The dates of on-farm checks. 

è  The presence of abscesses on the pigs’ skin, which may be due to vaccination or 

other injections. 

è  The identification of animals who required an additional dose of the vaccine, after 

on-farm checks. 

è  The number of vaccinated animals sent for slaughter. 

A sample template for the vaccination declaration is presented below. 

Figure 7.  Example of a template for the vaccination declaration60  

Documentation  on  vaccination  is  generally  paper-based.  Documents  are  completed 
manually  by  the  farmer  and  the  person  administering  the  vaccine  (there  may  be  cases 
where  the  farmer  is  also  the  person  administering  the  vaccine).  These  documents 
accompany each group of pigs when they are sent for slaughter. The driver of the transport 
vehicle delivers the documentation manually to slaughterhouses.  

It is also possible to transmit data on vaccination procedures with an electronic system61. 
This system can be accessed in real time by several people, including those responsible for 

60 Zoetis (n.d.) Implementation on-farm. Training program for the implementation of Improvac – Vaccine for the 

control of boar taint (unpublished) 

61  For example, the Endorsis platform developed by Zoetis is used in some countries outside the EU and is being 
implemented in Germany: https://www.endorsis.com/Login/Login.aspx?ReturnUrl=%2f. Other examples of 
platforms include TrazaImprovac, used in Spain: https://www.trazaimprovac.com/, and Global Vet Link, used in 
the US: https://user.globalvetlink.com/gvl2/login/auth.    

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the administration of the vaccine, the farmer, the vaccine supplier, and the slaughterhouse 
staff. This system simplifies the tracking and verification of vaccination data. 

In Spain, documentation accompanies vaccinated pigs and is delivered manually.  

Advantages 

è  This  supports  a  trustful  and  transparent  relationship  between  farms  and 

slaughterhouses 

è  Documentation  can  be  used  to  inform  statistical  records  at  slaughterhouses; 
specifically,  they  can  be  used  to  identify  and  address  vaccination  issues,  and 
therefore  improve  the  whole  vaccination  process.  The  vaccination  declaration 
enables to identify the person who administered the vaccine. Therefore, in case of 
boar taint issues it is possible to target potential interventions (such as re-training 
on  the  vaccination  process)  to  the  right  person.  This  help  reassuring 
slaughterhouses that farmers are committed to resolving problems if and when they 
appear. 

Disadvantages 

è  The preparation of documents may be time consuming  depending on  format  and 
level of detail. The time needed to prepare the documentation may be reduced by 
providing farmers with standardised templates that are easy to fill in. 

7.4  Q4. Slaughterhouses – uncastrated pigs: detect boar taint, quantify 

and manage positive carcasses 

This document lists good practice examples of dealing with boar taint at slaughterhouses. 
The  document  includes  information  on  (i)  detecting  boar  taint  and  (ii)  quantifying  and 
managing positive carcasses. The practices mentioned are all currently used in commercial 
operations in the EU. Other relevant practices at slaughterhouses, such as transport and 
handling, are not discussed in this document, but they are important since they can have 
an impact on the prevalence of boar taint. 

It is necessary to systematically detect boar taint in carcasses of entire males, in order to: 

  Separate out carcasses with boar taint and those without 

  Inform farmers, breeders, and feed producers of the level of boar taint so they can 

improve their practices accordingly 

  Reassure  buyers  (processors  and  retailers)  that  no  boar  tainted  meat  will  be 

unknowingly sold to consumers 

  Market meat from entire males with no detectable boar taint as a high value product 

The  most  widely  used  method  for  detecting  boar  taint  is  the  human  nose  method. 
Although  no  detection  method  is  fool-proof,  this  method  delivers  robust  results  when 
implemented correctly. It is considered best practice by many slaughterhouses and their 
suppliers and clients within entire male supply chains. This document presents numerous 
good practices for using the human nose method. 

Several chemical testing methods are also under development. They have yet to be used 
in commercial conditions and are therefore not discussed in this document.  

Making  the  transition  to  slaughtering  entire  males  requires  careful  consideration  and 
planning  on  the  part of  the  slaughterhouse.  The  following  guide  refers  to  practices  that 
may be of interest to slaughterhouses making such a transition. In addition to the practices 
described,  it  is  important  for  all  slaughterhouses  to  communicate  with  their  supply 
chain  and  customers  before  and  during  any  transition  to  slaughtering  entire  males. 

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Understanding  the  costs  and  benefits  to  other  parts  of  the  supply  chain  will  also  help 
slaughterhouses advocate for and lead the transition away from surgical castration. 

Things to consider 

Whatever method a slaughterhouse chooses for detecting or dealing with boar taint, this 
information should be provided to clients and suppliers. This can help to build trust along 
the supply chain and can help slaughterhouses address concerns regarding boar taint.  

7.4.1  Human nose - principle 

Figure 8.  Location of the neck fat 

All  human  nose  techniques  rely  on  trained 
testers  heating  and  then smelling  a  sample 
of  fat  on  each  carcass.  This  occurs  after  the 
carcasses have been cut in half and before the 
carcasses are cooled. 

DO use neck fat. The neck is easy to reach. 
The fat in this area is easily accessible. It can 
be heated without damaging the meat around 
it.  Some  techniques  also  heat  some  of  the 
muscle  around  the  fat,  so  that  both  types  of 
tissue are tested. 

DO NOT use abdominal fat for sampling boar 
taint.  Testing  carcasses  on  abdominal  fat  is 
more likely to lead to errors in the detection of 
boar taint. 

Things to consider 

Switching  to  the  human  nose  method  means 
having enough staff trained and available to 
carry out the tests.  

This  needs  to  take  into  account  the 
è 
speed  of  the  slaughter  line  and  the 
number  of  boars  anticipated.  The  human 
nose  method  is  sustainable  only  if  there  is  a 
the 
of 
continuous 
slaughterhouse.  

boars 

flow 

at 

The  role  of  tester  may  be  unpleasant, 
è 
therefore the need and benefits of the practice 
need to be communicated well to operators 
to make it accepted. 

One must take into account the need for 

è 
the assessors to take regular breaks. 

è  Processing boars does not only require more staff time for conducting smell tests. 

Additional staff time is also required to cut out male parts from the carcass. 

For example, one slaughterhouse has used 1 tester per slaughter line at 500 boars/hour, 
regularly replaced every 30 minutes. 

Many slaughterhouses  that  use the human  nose  method  rely on their own staff, hired 
and trained to assess boar taint. One Dutch slaughterhouse estimated that this costs less 
than €1 per test. 

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Others borrow trained operators from other slaughterhouses. External contractors will 
generally charge for their staff by the hour. For example, one contractor charges €65 per 
hour  for  a  minimum  of  four  hours.  In  the  Netherlands,  the  costs  of  using  external 
contractors for human nose testing was calculated to be equivalent to €2.10 per carcass. 

Others hire external contractors. 

Case study: The human nose scoring system of a major Dutch slaughterhouse 

A Dutch slaughterhouse has developed its own boar taint detection method based on the 
human  nose.  The  company  is  an  EU  market  leader  with  over  10  years  of  experience  in 
producing  boar  meat.  It  operates  both  in  the  UK  and  in  the  Netherlands,  slaughtering 
thousands  of  male  pigs  each  week.  Further  details  on  this  case  study  are  provided  in 
Section 5.2.1. 

7.4.2  Human nose method - variants 

Variants of the human nose methods exist:  

  on  line:  the  detection  of  boar  taint  occurs  as  carcasses  move  through  the 
slaughterhouse. Slaughterhouses use the hot air/hot iron technique, or gas-powered 
soldering irons for on line testing.  

  off line: fat samples are collected on the carcasses and then taken elsewhere (such 
as  a  laboratory)  for  analysis.  Slaughterhouses  use  the  hot  water  or  microwave 
technique for off line testing. 

7.4.2.1  Hot air/hot iron method (on line) 

A  tester  places  a  welding  device  against  the  neck  of  the  pig  carcass  for  2-3  seconds. 
Immediately  afterwards,  a  tester  smells  the  carcass  and  judges  whether  boar  taint  is 
present. This is then recorded. 

The number of testers depends on the speed of the slaughter line: in faster operations two 
testers to work together. Slower lines may only require one.  

Slaughterhouses  use  hand-held  hot  air  welding  devices.  These  may  be  modified  to 
include a guide bar (as in Figure 2). That helps orient and stabilise the operator’s hand and 
standardises the distance between the heating device and the carcass.  

Alternatively, a hand-held soldering iron with a hot iron tip may be used. Where a metal 
tip is used, it should be cleaned regularly.  

Suppliers of welding equipment used by slaughterhouses include Leister and Weller. Such 
equipment can be purchased at DIY or hardware stores. 

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Figure 9.  The hot air method 

Advantages 

è This  allows  for  rapid  testing  on  line  and 
therefore does not have any impact on the speed 
of the slaughter line. 

è The equipment is low cost. 

Disadvantages 

è The  equipment  tends  to  be  cabled,  and  an 
electrical connection is therefore needed. 

è Operators using  hot  air  devices  can  risk  being 
burnt.  

Things to consider 

Soldering equipment comes with different wattages and settings. The appropriate wattage 
or temperature setting may differ depending on slaughterhouse conditions or the type of 
equipment used. It may be necessary to experiment with different options before deciding 
on what equipment is most appropriate within a certain setting.  

7.4.2.2  Gas-powered soldering iron (on line) 

This method is largely similar to the hot air/hot iron method but differs in the source of 
heat used. Here, a gas flame is used to torch the neck of the pig carcass or to heat a metal 
plate used to heat the fat on the carcass.  

Gas  powered  soldering  irons  are  small,  portable  and  cordless.  Suppliers  include  Weller. 
This equipment can be purchased at DIY or hardware stores. 

Advantages 

è  This allows for rapid testing on line and therefore does not have any impact on the 

speed of the slaughter line. 

è  The equipment used is cordless and can be moved easily. 

è  The equipment is low cost. 

Disadvantages 

è  The use of open flame can lead to a risk of burning and fire. 

Things to consider 

Gas  canisters  need  to  be  replaced  frequently.  This  cost  should  be  considered  for 
slaughterhouses processing larger numbers of entire males.  

7.4.2.3  Hot water method (off line) 

A 5-gram sample of lard is collected from the neck of the carcass. It is taken to a testing 
room or  laboratory. The  sample is  placed in  a test tube,  beaker or  conical flask. Boiling 
water is poured over the sample and it is covered.  

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The tester  waits until  the  sample  has  cooled  slightly,  to  approximately  80  degrees.  The 
covering is then removed and the vapours are sniffed by the tester to determine whether 
boar taint is present. The result is then recorded. 

7.4.2.4  Microwave method (off line) 

A  5 to  20-gram sample of  fat  is  collected  from  the  neck of  the  carcass.  It  is  taken  to a 
testing room or laboratory. The sample is placed in a container, covered with a lid and then 
heated using a microwave.  

The covering is then removed and the sample is smelled by the tester to determine whether 
boar taint is present.  

Advantages 

è  These methods are low cost. 

è  These  methods  are  suitable  for  smaller  operations,  where  fewer  boars  are 

processed. 

è  These  are  reliable  methods  for  re-testing  carcasses  as  part  of  quality  control 

procedures of on line testing. 

Disadvantages 

è  Off line methods are inefficient as compared to the hot iron or open flame and only 

suitable for off line testing. 

Things to consider 

For off-line methods, slaughterhouses need a robust numbering system for samples and 
carcasses to ensure that samples and carcasses are matched correctly. 

7.4.3  Human nose method - Alternative taint scales 

Slaughterhouses that use the human nose method have used scales to record the tester’s 
assessment.  These  scales  are  one  of  the  tools  that  enable  differentiating  between 
different levels of boar taint, which can provide more options for marketing tainted meat 
on the markets the meat is intended for. Scales are also one of various tools that can be 
used to ensure consistency in boar taint detection. 

7.4.3.1  Binary scales (Tainted/untainted) 

Some slaughterhouses use a simple yes/no system: testers only need to establish whether 
boar taint is detectable or not.  

Advantages 

è  This is a simple distinction, which makes it easier to train testers.  

Disadvantages 

è  This  limits  options  for  the  classification  of  boar  tainted  meat,  its  processing  and 

commercialisation on different markets. 

Things to consider 

This method requires that operators share a consistent and common understanding of boar 
taint threshold.  

7.4.3.2  Scales with multiple levels 

Some slaughterhouses allow operators to assess the presence of taint on a scale (such as 
from 0 to 4, where 0 means “normal pork smell” and 4 “strong boar taint”). This provides 
more nuance and detail. 

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Advantages 

è  This  allows  for  several  options  for  the  classification  of  meat,  its  processing  and 

commercialisation on different markets. 

è  This enables more detailed feedback to farmers, breeders, and feeding producers, 

than when using a binary (yes/no) scale. 

è  Granular  scales  enable  better  identification  of  “borderline”  carcasses  that  may 

require re-testing before classification. 

Things to consider 

Testers need to have a good understanding of how to use the scale. This method therefore 
requires thorough training and enhanced quality assurance checks. 

7.4.4  Human nose method – Selection and training of testers 

Particular care needs to be devoted to the selection and training of testers. 

Selection of testers is important because: 

  Some people are unable to detect androstenone 

  Some people are hyper-sensitive to androstenone 

Testers  should  not  be  selected  from  either  of  these  groups.  To  evaluate  the  ability  of 
individuals to act as testers, some slaughterhouses use smell kits. These can be purchased 
from an external contractor.  

Testers need to be trained. It is important that assessors are not only able to detect boar 
taint, but also that they are able to distinguish it from other similar smells. Boars might 
present other odours that will not impact the quality of the meat but could be confused for 
boar taint.  

Training is sometimes carried out in-house. External contractors can be relied on if there 
is no capacity or expertise in house. 

External contractors offering training and services in the human nose method include ELFI 
Analytik  GbR,  SGS  and  DLG  e.V.  in  Germany,  the  Danish  Technological  Institute  in 
Denmark, ILVO in Belgium and Kiwa CMR in the Netherlands.  

Initial training can take between 4 to 6 weeks, including a first phase of a few days in the 
laboratory, followed by several weeks on the slaughter line alongside a trainer.  

Training includes also other aspects than detecting boar taint, such as procedures for the 
classification of carcasses.  

Assessors are trained at hiring and then periodically retrained. 

7.4.5  Human nose method – procedures to prevent habituation 

Testers are at risk of becoming habituated to the smell of boar taint over time. As a 
result, their ability to detect boar taint may decrease. Slaughterhouses have used various 
solutions to prevent habituation. 

7.4.5.1  Taking breaks 

Many slaughterhouses use different testers. They rotate testers every 20 or 30 minutes, 
or after a certain number of carcasses (100 in one example). This also means that once a 
tester has detected boar taint, they must take a break before continuing. A tester that is 
relieved from their ‘human nose’ role may take on another task on the line, until they are 
called back. 

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Advantages 

è  Taking breaks helps keep testers consistent in their judgments. 

è  Operators can be testers and perform other roles on the line throughout the day. 

Disadvantages 

è  For staff to take breaks, several trained testers must be available at any given time 

the line is operating. 

7.4.5.2  Nose cleansers 

To  avoid  smell  habituation  some  slaughterhouses  use  a  'nose  cleanser',  such  as  coffee 
grounds  or  menthol. A  cleanser  can  be  sniffed  between  samples,  allowing  the  tester  to 
'reset' before moving on. If clothing is clean, smelling the inner arm may also be used as 
a ‘reset’ method.   

Advantages 

è  A cleanser can be provided to assessors at low cost. 

Disadvantages 

è  The use of a cleanser may not be easily integrated into rapid on line testing.  

Things to consider 

Some slaughterhouses have found that although cleansers are offered to smell assessors, 
they  are  used  very  little.  Some  experimentation  may  be  needed  to  determine  how 
cleansers can best be incorporated in on line detection.  

7.4.6  Human nose method – Quality control 

Quality control checks help maintain a robust detection process at the slaughterhouse.  

7.4.6.1  Using multiple testers 

When one tester detects boar taint and the animal is identified as such, a sample is taken 
and a second tester confirms whether boar taint is present. The second opinion allows the 
slaughterhouse  to  avoid  false  positives  and confirm  the  presence of  boar taint.  If  doubt 
remains after a second test or if there have been a high number of tainted carcasses within 
a particular batch of animals, it may go to another tester for a third opinion.  

Advantages 

è  The use of multiple testers minimises the risk of error. 

Disadvantages 

è  For multiple testers to be available, additional trained staff must be available.  

è  This  requires  a  combination  of  both  on  line  and  off  line  techniques  and 

infrastructure.  

7.4.6.2  Parallel controls 

Slaughterhouses can establish protocols for parallel controls. These should occur regularly, 
such as by re-testing a sample of tainted carcasses on a weekly basis. 

Testing  can  be checked against laboratory  results that detect  the presence of chemicals 
responsible  for  boar  taint.  Testing  can  also  be  verified  through  an  additional  round  of 
human nose testing.  

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This  information  can  be  used  to  compare  individual  assessors  and  ensure  detection  is 
consistent and reliable.  

Where external contractors are used for training, they may also provide regular re-training 
and assessment services, to ensure that detection remains reliable. 

Advantages 

è  The use of parallel controls can reinforce trust in the detection system.  

Disadvantages 

è  Laboratory  testing  may  take  additional  time  to  process  and  cause  a  delay  in 

feedback. 

Things to consider 

Parallel controls are required by some assurance schemes. These schemes, including QS 
in Germany  and IKB in  the  Netherlands,  may  be  able to  provide  additional  guidance on 
what quality control system best suits a particular slaughterhouse and detection procedure.  

7.4.6.3  Statistical analysis 

Slaughterhouses analyse boar taint detection data from one day to another, and from one 
tester to another. This enables them to investigate possible inconsistencies, which can then 
be addressed by, for example, re-training a tester.  

7.4.7  Human nose method - Protocols for harmonising human nose testing across 

supply chains 

Some assurance schemes have begun developing standards for boar taint detection. These 
standards are a tool for the harmonisation of human nose testing across supply chains. 

Human  nose  testing  protocols  can  be  established  as  a  framework,  stipulating  certain 
conditions that the human nose testing procedure in place needs to fulfil. Such frameworks 
do not define the specific methods that should be used for human nose testing, but instead 
set out criteria required for a robust and verifiable detection system.  

For example, the framework established by QS includes the following:  

•  Procedures  and  instructions  must  be  in  place  defining  how  detection  is  performed, 
including how long each operator can continuously detect, how operators are monitored 
and how parallel controls occur.  

•  Operators should be given initial training and regular additional training.  

•  There  must  be  practices  in  place  to  ensure  that  tainted  carcasses  can  be  easily 

separated.  

•  The  slaughterhouse  must  provide  feedback  to  their  farmers  and  suppliers  on  the 

instance of boar taint within each batch.  

The ‘Beter Leven’ label in the Netherlands has also developed a similar, but more detailed 
framework.  

Establishing  protocols  for  human  nose  testing  also  offers  the  opportunity  to  further 
harmonise methods between certifiers and countries.  

Case study: Harmonisation of standards for HNS in Europe - The case of QS and 
IKB 

In  2012,  two  European  quality  assurance  organisations,  QS  in  Germany  and  IKB  in  the 
Netherlands  agreed  on  a  common  framework  for  boar  taint  detection  using  the  Human 

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Nose  Scoring  (HNS)  system.  Further  details  on  this  case  study  are  provided  in  Section 
5.2.1.  

Advantages 

è  These  standards  offer  a  framework  for  slaughterhouses  to  develop  and  manage 

human nose testing on entire male carcasses. 

è  Standards embedded into assurance schemes support mutual recognition and trade 

of meat from entire males across EU countries 

Disadvantages 

è  Some requirements may be difficult for some slaughterhouses to implement.  

7.4.8  Non-detection  

In some countries, the issue of boar taint is addressed entirely through on-farm practices 
and by slaughtering animals at a lower weight. In other countries, no detection is used and 
boar taint is addressed entirely through processing and masking.  

Weight cut-offs differ depending on the source but are generally between 100 kg and 115 
kg, although there are also some instances where entire males are being slaughtered at 
up  to  130  kg.  Processing  techniques  to  address  boar  taint  are  described  in  Q6  (Section 
7.6).  

Entire  males  slaughtered  at  lower  weights  are  considered  to  be  low-risk  for  boar  taint, 
therefore  no  detection  is  used  at  the  slaughterhouse  and  the  meat  is  not  processed 
separately. It is assumed that the risk for boar taint is low enough that no further steps 
are required to address it.  

However, age is a better indicator for boar taint than weight, so it is likely that some pigs 
slaughtered at a low weight (slow growers) will still be at risk for boar taint.  

Advantages 

è  There are no costs of detection involved. 

Disadvantages 

è  Slaughtering  at  a  low  weight requires  herd management  to  ensure  that  all  entire 

males are slaughtered before reaching the cut-off weight. 

è  This could limit revenue per pig that farmers may achieve by rearing bigger animals. 

è  Tainted meat may enter the supply chain. 

Things to consider 

è  Weight cut offs are a helpful proxy for age but are not fool-proof. It may be helpful to 

have discussions with farmers or suppliers about age and growth rates.  

è  Upper and lower weight limits are stipulated by the processor and are often influenced 
by  the  market  or  set  by  quality  assurance  schemes.  Slaughtering  at  lower  weights 
might therefore require discussions within the supply chain.   

7.4.9  Supply chain management 

7.4.9.1  Keeping records and providing feedback 

Some slaughterhouses keep records of all carcasses that present boar taint and their origin. 
This  information  can  then  be  used  to  provide  feedback  to  farmers  if  there  is  a  high 

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occurrence of boar taint among their animals. Where supply chains are more integrated, 
feedback may also be provided to feed suppliers or breeding companies.  

QS in Germany and IKB in the Netherlands require slaughterhouses that deal with entire 
males to provide feedback on the testing results to farmers, alongside feedback on other 
factors related to the health of the pig and quality of the meat.  

Advantages 

è  Providing feedback to farmers can help reduce instances of boar taint in the supply 

chain 

è  Providing  feedback  to  breeders  or  feed  providers  can  help  improve  existing 

breeding/feeding solutions 

Disadvantages 

è  The use  of negative  feedback  may  lead  to  farmers  re-adopting  castration  unless 

coupled with guidance or economic incentives. 

è  This requires additional controls and systems to be in place, including data capture, 

database storage and analysis of data 

7.4.10  Penalties for boar taint 

Slaughterhouses  may  penalise farmers  that supply  entire  males  with high  levels  of  boar 
taint.  

The  return  for  slaughterhouses  on  tainted  carcasses  is  significantly  lower  than  for non-
tainted carcasses. In the Netherlands, for example, tainted carcasses return around €25 
less than non-tainted carcasses. Penalties can therefore help slaughterhouses reduce this 
risk. 

Advantages 

è  This provides an incentive for farmers to adopt better farm-level practices. 

è  This helps balance the risks for the slaughterhouse since boar tainted meat has less 

value. 

Things to consider 

Using penalties may impact the relationship between the slaughterhouse and farmer and 
could lead to a loss of trust. The use of penalties should therefore be considered alongside 
other measures that offer positive incentives to encourage farmers to raise entire males.  

7.4.11  Farm audits 

For  special  markets  or  for  certain  certification  programmes,  some  slaughterhouses  (or 
contracted auditors) may undertake physical farm visits and inspections to ensure that no 
animals are undergoing castration and that other animal welfare practices are compliant 
with  the relevant  standard.  Such inspections  can  take  place once  a  year  with  additional 
random audits to ensure adequate controls. Some slaughterhouses may choose to target 
farms based on past performance. For certification programmes, the costs of such audits 
may be covered by other actors in the supply chain.  

Advantages 

è  Audits can help increases confidence in farm welfare standards. 

è  Certification can add value to meat, increasing profitability for farmers.  

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Disadvantages 

è  Audit programmes come with additional costs.  

è  Audit programmes cannot guarantee compliance between visits. 

7.4.12  Same-sex groups 

Some slaughterhouses require farmers to supply pigs to the slaughterhouse in same-sex 
groups  only.  This  can  help  slaughterhouses  with  the  logistical  issues  of  having  mixed 
carcass types on line.  

Some slaughterhouses  choose  to have  certain  times  where no  boars  are  allowed on  the 
slaughter  line.  All  the  meat  produced  at  this  time  is  intended  for  customers  or  product 
categories that will not or cannot use boar meat. This requires scheduling arrivals and good 
coordination with farmers / suppliers / transporters. 

Advantages 

è  This  may  contribute  to  a  reduction  in  boar  taint  instance  due  to  more  reliable 

matching of samples to carcasses. 

è  This ensures all boars are dealt with at once, making testing more efficient. 

Disadvantages 

è  This may be challenging for farmers who raise their pigs in mixed groups. 

Things to consider 

Some farmers may already raise pigs in same-sex groups and will find it easy to transport 
boars and gilts separately. Some farmers may have concerns, however, that sex separation 
leads to increased aggression among boars and will prefer other grouping arrangements. 
As farmers’ experiences differ on this subject, it may be helpful to have a conversation on 
these issues before transitioning.  

7.4.13  Classification of carcasses 

Classification of carcasses allows slaughterhouses to deal with groups of tainted and non-
tainted carcasses  after  detection.  The  tainted  carcasses can then  be  processed in  a  way 
that  minimises  the  issue  of  boar  taint.  For  slaughterhouses  that  are  also  involved  in 
processing,  this  may  mean  using  the  meat  for  appropriately  processed  products. 
Processing may not be feasible for some operations, and tainted carcasses are instead sold 
to other special markets. Slaughterhouses report different instances of tainted carcasses, 
but most appear to range between 1% and 3%. 

Things to consider 

There must be sufficient space in the cold store to separate carcasses on the basis of boar 
taint. 

7.4.14  Electronic classification of carcasses 

When an operator detects boar taint using on-line testing technology, they may be able to 
indicate to an electronic system (such as by pressing a button) that the carcass is tainted. 
Carcasses are hung on hooks embedded with electronic chips, and once a signal indicates 
the presence of boar taint, the carcass is derailed to be dealt with separately.   

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Advantages 

è  This offers an efficient and streamlined system to both record instances of taint and 

separate tainted carcasses. 

è  Electronic  classification  systems  can  be  used  to  streamline  other  slaughterhouse 

processes. 

Disadvantages 

è  The infrastructure required is likely to be costly if  existing  electronic systems are 

not already in use.  

7.4.15  Manual classification of carcasses 

In some slaughterhouses, when boar taint is judged to be present, operators use a physical 
indicator to mark the carcass. Physical indicators might be a piece of string tied to the pig's 
leg  or  a  stamp  displayed  visibly  on  the  carcass.  Operators  may  also  keep  a  written  (or 
electronic) record for statistical purposes.   

Advantages 

è  There is a lower investment cost compared to electronic classification.  

Disadvantages 

è  This does not automatically include classification information in electronic records. 

7.5  Q5.  Slaughterhouses  –  vaccinated  pigs:  obtain  assurance  from 

farmers that vaccinated pigs do not contain detectable boar taint 

This document provides good practice examples that can be used by business operators to 
build trust in vaccination against boar taint. This document presents practices which are 
used in commercial operations.  

Many slaughterhouse operators, and their customers, remain sceptical of the proposition 
that vaccination is an effective means of preventing boar taint. Lack of trust in vaccination 
as a means of preventing boar taint is an issue across the supply chain. This is particularly 
the case where supply chains are not well integrated and slaughterhouses lack confidence 
that  assurance  procedures  have  been  fully  carried  out  on-farm.  Consequently,  building 
trust  in  vaccination  against  boar  taint  requires  engagement  with  many  different  actors, 
from  farmers  to  retailers  and  consumers.  The  following  practices  are  used  to  increase 
confidence in vaccination against boar taint and its effectiveness. Understanding the costs 
and benefits to other parts of the supply chain will also help slaughterhouses advocate for 
and lead the transition away from surgical castration. 

7.5.1  Checks to verify that vaccination has been administered correctly  

Some slaughterhouses choose to conduct checks for boar taint in vaccinated pigs on the 
slaughter line or off-line. These checks may involve on-line sensory testing of boar taint, 
or off-line chemical testing for substances associated with boar taint.  

Checks can be done randomly or can be based on risk factors. Risk-based checks are likely 
to be more efficient than random checks. For risk-based checks, the frequency of checks 
may be adjusted to the slaughterhouse and farmer and their experience with vaccination 
against  boar  taint.  More  frequent  checks  may  be  conducted  for  less-experienced 
slaughterhouses and/or farmers. The person responsible for receiving the animals in the 
lairage may also check for the physical signs of the effectiveness of vaccination on arrival. 
Targeted checks may therefore be conducted on batches of pigs which show signs that the 
vaccine may have not been administered correctly.  

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Using these checks, slaughterhouses can then communicate results to farmers and to the 
next stage of the supply chain.  

Advantages 

è  Checks enhance industry-wide confidence in vaccination against boar taint. 

è  The results of checks can be used to set priorities for future risk-based checks. 

è  The results of checks can also be reported back to farmers, so that they can take 
the measures necessary to address the incorrect administration of the vaccine. 

Disadvantages 

è  If checks are not based on any specific risk factors, they may not be efficient. 

Things to consider 

Checks  performed  by  the  slaughterhouse  should  be  thoroughly  documented,  and  then 
shared  with  the  farmers.  This  is  crucial  to  avoid  fuelling  distrust  in  the  relationship. 
Slaughterhouses therefore need an efficient process for collecting data on checks, which 
may be for example an electronic system. 

7.5.1.1  Human nose method 

Some slaughterhouses may use the same checks and boar taint detection techniques that 
are  used  for  entire  males.  Integrating  checks  for  vaccinated  pigs  with  checks  used  for 
entire males can improve efficiency and reduce costs of checks. 

For  details on the  human  nose  method, including  advantages  and  disadvantages  please 
read the document titled “Slaughterhouses – uncastrated pigs: detect boar taint, quantify 
and manage positive carcasses” 

7.5.1.2  Blood test for testosterone 

One  method  for  assessing  whether  vaccination  has  been  successful  is  testing  groups  of 
pigs for testosterone levels. Testosterone levels can be checked through a  simple blood 
test. Many human healthcare providers offer these tests and results can be received within 
24  hours.  The  results  of  this  test  can  then  be  used  to  determine  whether  animals  have 
been properly vaccinated and therefore whether they are at risk for boar taint.  

Vaccinated pigs generally have testosterone levels between 5 to 100 ng/dl. Entire males, 
by  contrast,  generally  have  testosterone  levels  between  500  to  1500  ng/dl.  However, 
testosterone levels are cyclical and there is no definitive cut off. This test is therefore best 
used for assessing batches of pigs. If testing shows that a batch of pigs contains several 
males with high testosterone levels, it is likely that vaccination has not been done properly 
on this group of pigs. These pigs can then be subjected to additional sensory testing and 
feedback can be provided to the farmer.   

Advantages 

è  This identifies groups of pigs most at risk for boar taint. 

è  This  allows  the  slaughterhouse  to  provide  feedback  to  farmers  on  the  success  of 

vaccination. 

è  This method is faster and cheaper than chemical testing (see below).   

Disadvantages 

è  Requires slaughterhouses have additional capabilities to perform blood tests. 

è  The tests incur additional costs 

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è  Without a validated cut-off value for testosterone levels, false-negative results may 

occur.  

Things to consider 

è  The optimal number of pigs to be tested depends on the level of confidence required 

by slaughterhouses and their partners. 

è  Tests cost between €8 and €10 per test.  

7.5.1.3  Chemical testing of a fat sample 

The slaughterhouse  can take  a  fat  sample  from  a  small  number of  vaccinated  pigs  and 
send these to an external laboratory for chemical testing. This analysis is used to detect 
the levels of androstenone in the fat. Samples that contain above 1 µg/g of androstenone 
are  considered  to  be  positive for  boar  taint.  This  provides  a  quantifiable indicator of the 
level of boar taint present in the tested carcass.   

Advantages 

è  This type of testing does not require slaughterhouses to have any boar taint testing 

capabilities on-site. 

è  Chemical testing offers quantifiable feedback on the presence of boar taint. 

Disadvantages 

è  This  is  not  a  rapid  testing  method  so  does  not  allow  for  tainted  carcasses  to  be 

quickly removed from the line.  

è  This type of testing is only suitable for a small number of carcasses. It will likely give 
an incomplete picture of the level of boar taint in vaccinated pigs. Tainted meat may 
enter the supply chain as a result. 

è  This type of testing may be too expensive for some slaughterhouses. If 1 per cent 
of carcasses are tested, this will cost around 0.03 EUR per kilo of meat received from 
vaccinated pigs.  

Things to consider 

The  use  of  this  method  depends  on  the  need  for  assurance  in  the  supply  chain.  The 
additional costs need to be balanced by price incentives.  

7.5.2  Bonus payments 

Although some slaughterhouses treat vaccinated pigs as boars and pay less for them (as 
compared to surgically castrated pigs), others do not issue penalties or choose to pay more 
(for  example,  an  extra  0.01  EUR  per  kg  is  paid  to  farmers  in  Belgium  for  carcasses  of 
vaccinated pigs). The price premium for vaccinated pigs is made possible by certification 
schemes and by demand from retailers who are interested in selling meat from vaccinated 
pigs.  

Advantages 

è  Bonus payments increase the profitability of using vaccination against boar taint for 

farmers. 

è  Bonus payments contribute to aligning the interests of all actors in the supply chain. 

è  Bonus payments incentivize farmers to be particularly attentive to the risk of boar 

taint in the animals they supply to slaughterhouses. 

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7.6  Q6.  Food  processors  –  uncastrated  pigs:  deal  with  meat  with 

detectable boar taint 

This document lists good practice examples of dealing with meat with detectable boar taint 
at  the  processing  stage.  The  practices  mentioned  are  all  currently  used  in  commercial 
operations in the EU. 

Different processing techniques are used to mask boar taint in tainted meat. They enable 
the  sale  and  consumption  of  tainted  meat  in  various  markets,  including  those  where 
consumers are sensitive to boar taint. Where appropriate, many of the practices described 
below can be used in combination. 

Making the transition to processing meat from entire males requires careful consideration 
and planning on the part of processors. The following guide refers to practices that may 
be of interest to processors making such a transition. In addition to the practices 
described, it is important for all slaughterhouses to communicate with their supply 
chain and customers before and during any transition to processing meat from entire 
males. Understanding the costs and benefits to other parts of the supply chain will also 
help processors advocate for and lead the transition away from surgical castration. 

Things to consider 

è  When it comes to processing pig meat, boar taint is only one of several relevant factors. 
Other factors, such as the ratio of fat to lean meat, pH levels, tenderness and fat quality 
(degree of unsaturation, iodine value), are also relevant. These are not covered in this 
document.  They  need  to  be  considered  alongside  boar  taint  when  transitioning  to 
processing meat from entire males.  

è  For  all  techniques, their  effectiveness  depends on the level of  boar taint  in the  meat 

before it is processed. 

7.6.1  Use of tainted meat for products that are consumed cold 

Boar taint tends to be less detectable when meat/meat products are consumed cold (for 
example, cold cooked ham or cold smoked meat).  

The effectiveness of this approach depends on the level of taint in the raw material as well 
as on the level of fat required for the product. That is because the substances responsible 
for boar taint accumulate mostly in the fat.  

Things to consider 

Some  products intended  for  cold  consumption may  in some  instances  end  up  consumed 
warm  –  such as where meat  is included as a pizza topping. It is therefore important to 
consider actual likely end use of products when choosing where to use tainted meat.  

7.6.2  Diluting/Mixing 

Tainted and non-tainted meat can be mixed to produce sausages and other minced foods. 
Dilution reduces the proportion of substances responsible for boar taint in the final product.  

There should be enough non-tainted meat in this mix to make sure the final product does 
not have boar taint – this depends on several factors, including how strongly tainted the 
meat is before dilution, the amount of fat in the meat, the type of processing used and the 
intended method of consumption.  

This  technique  requires  a  relatively  precise  assessment  of  the  level  of  boar  taint  to 
determine what quantity of untainted meat it must be mixed with. This in turn depends on 
the use of scales more granular than only untainted/tainted for measuring boar taint with 
the human nose method. 

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Advantages 

è  The practice is effective when tainted meat is mixed with enough non-tainted meat.  

Disadvantages 

è  This technique may be more difficult to use when the level of boar taint is not clearly 

assessed earlier in the chain, in slaughterhouses. 

è  This technique applies only to minced products (sausages and other minced foods): 
for other meat products (e.g., ham), all of the meat must come in a single cut from 
a single pig, meaning that dilution is not an option. While any part of the pig can be 
minced  in  theory,  mincing  the  highly  valuable  parts  of  the  pig  is  avoided  for 
economic reasons. 

7.6.3  Dry curing 

Dry  curing  is used  for the  production of cured ham. It  involves  rubbing  a  piece  of meat 
with a dry-cure mixture of salt and other ingredients. Dry curing produces a salty product. 

Advantages 

è  Dry  curing  changes  the  taste,  aspect,  smell  and  texture  of  the  meat  (e.g.  salt, 

nitrites). This may help reducing the perception of boar taint. 

Disadvantages 

è  Dry  curing  alone may  not  be  sufficient to  reduce  the  perception  of  boar  taint. By 
contrast, there might be a further concentration of the taste in the dried product. 
Additional processing may be needed to mask this taste, such as the use of spices.  

7.6.4  Fermentation 

Fermentation  is  used  for  production  of  salami-type sausages.  Sometimes  this  is  applied 
together with smoke and/or edible mould. 

Use of tainted meat in pickled products may also help. 

Advantages 

è  Fermentation changes the taste, aspect, smell and texture of the meat, which helps 

reduce the perception of deviant smell and taste of boar meat. 

7.6.5  Smoking 

In  sausages  and  cooked  hams,  liquid  smoke  can  be  used  so  it  is  distributed  within  the 
product as compared to “real smoke” which only can be applied to the outer surface.  

Advantages 

è  This contributes to masking boar taint. 

Disadvantages 

è  There  is  little  information  on  how  intense  the  smoking  process  should  be  to  be 

effective. 

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è  Smoking  cannot  be  used  excessively  because  it  increases  the  concentration  of 
polycyclic  aromatic  hydrocarbons  (PAHs)62  that  are  known  to  be  carcinogenic 
substances. 

7.6.6  Thermal treatment 

Tainted  meat  can  be  heated  in  an  open  cooking  system  before  further  processing  (for 
wiener  or  liver  sausages).  Thermal  treatment  may  also  involve  quickly  decreasing  the 
temperature of meat and storing it at colder temperatures.  

Advantages 

è  Heating during processing, especially in the production of wiener or liver sausages, 

reduces boar taint concentration. 

7.6.7  Use of spices 

Spices are used on boar tainted meat to produce sausages (e.g. chorizo) and marinated 
meat products for fresh meat consumption.  

Advantages 

è  The use of spices helps reduce the perception of boar taint in meat products such 

as sausages and marinated fresh meats.  

Disadvantages 

è  The amount of spices per kilo of meat must not exceed a certain proportion to avoid 

dominating the product. 

è  Spices  change the taste,  aspect,  smell  and texture  of the meat,  which  may repel 

certain consumers.  

7.7  Q7. Retailers and food services – uncastrated pigs: promoting meat 

from uncastrated pigs  

This document lists good practice examples for the marketing of meat from entire males, 
at retail outlets or in the food service sector. The document includes information on (i) how 
to increase the market value of meat from uncastrated pigs and (ii) how to prevent meat 
with detectable boar taint reaching consumers. The practices mentioned are all currently 
used in commercial operations in the EU.  

Making the transition to selling meat from entire males requires careful consideration and 
planning on the part of the retailer. The following guide refers to practices that may be of 
interest to retailers making such a transition. In addition to the practices described, it is 
important for all retailers to communicate with their suppliers before and during any 
transition to selling meat from entire males. Understanding the costs and benefits to 
other parts of the supply chain will also help retailers advocate for and lead the transition 
away from surgical castration. 

Things to consider 

Consumers perceive boar taint in different ways, and this perception may differ depending 
on  the  product.  Many  consumers  are  unaware  of  the  issue  of  boar  taint  and  may  not 
understand why their meat smells bad. Many consumers are also unaware of the issue of 

62 These include benzoanthracene, benzofluoranthene, benzopyrene, dibenzoanthracene, and indenopyrene. 

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pig castration. These are important considerations when developing strategies to promote 
meat from uncastrated pigs.  

Case study: Delhaize’s successful marketing of meat from non-castrated pigs 

In  June  2018,  Belgian  retailer  Delhaize  launched  its  new  castration-free  pork  products 
under  its  “Better  for  Everyone”  (Mieux  pour  Tous  /  Beter  voor  Iedereen)  label,  a  label 
established in 2014 with a focus on nutritional quality and sustainability.  

Case study: Lidl Belgium’s move to entire males 

In 2012, Lidl Belgium decided to move fully to the sale of meat from entire, non-vaccinated 
pigs. Further details on these case studies are provided in Section 5.3.1. 

7.7.1  Marketing techniques 

Retailers have used marketing campaigns to increase the value of meat from uncastrated 
pigs. Techniques used to avoid boar tainted meat ending on shelves are the reliance on an 
agreed set of specifications.  

7.7.1.1  Marketing campaigns 

Retailers are often reluctant to communicate about non-castration practices to consumers. 
Therefore, marketing messages addressed to consumers generally do not mention the fact 
that  the  animals  are  not  castrated.  Rather,  these  messages  generally  mention  broader 
better animal welfare standards. That is not always the case, however, and a few retailers 
have also communicated about stopping castration in pig production.  

Marketing  campaigns  might  also  emphasise  other  benefits  to  non-castration  alongside 
animal welfare, such as environmental or human health benefits.  

In Belgium, Delhaize has recently included and publicised a ‘castration free’ policy for one 
of its pork labels.63 The marketing for this label highlights the absence of castration, but 
also mentions several other aspects of this label: 

•  The meat has  been  carefully  selected  for  taste,  and  comes  from  a  specific low-taint 

breed 

•  Pigs  are  fed  a  balanced  diet  which  also  contributes  to  human  health  (through  the 

inclusion of omega-3 fatty acids)  

•  The  production  is  entirely  Belgian  and  farmers  receive  an  incentive  per  animal  and 

reimbursement for additional feed costs; and 

•  There is a lower need for antibiotic use and therefore reduced use of antibiotics in the 

rearing of the pigs.   

Rather than referencing it as part of a broader animal welfare policy, this example includes 
non-castration  and  better  welfare  alongside  taste,  quality,  human  health,  an  appeal  to 
supporting local farmers and environmental concerns.  

Advantages 

è  Marketing  meat  from  uncastrated  pigs  with  ‘better  animal  welfare’  messages 

matches the growing interest from EU consumers about animal welfare.  

è  Consumers are made aware of the topic of pig castration. 

63 Delhaize. (2018) Delhaize kiest voor exclusief varkensras met nog meer smaak en nog meer oog voor dierenwelzijn. 

Available at: https://www.delhaize.be/press_overview:exclusief-varkensras   

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Things to consider 

è  The  provision  of information  about non-castration  can  usefully  be  combined  with 
other messages on health, taste, and environmental benefits of raising entire males. 

Further reading 

Aldi  in Germany have included  a  move  away  from  pig castration in  their  animal  welfare 
purchasing  policy.  More  details  of 
this  are  available  at:  https://www.cr-
aldinord.com/2017/wp-content/uploads/sites/4/2018/05/ALDI-North-Germany_National-
Animal-Welfare-Purchasing-Policy.pdf  

7.7.1.2  Buyer specifications addressed to suppliers 

Producers hoping to sell to a retailer are required to comply with its product specifications. 
Specifications may forbid surgical castration of pigs and/or require the use of measures to 
reduce  boar  taint  (e.g.  breeding  or  feeding  techniques,  improved  housing  conditions). 
These specifications are the principal mechanism retailers have used to ensure that boar 
tainted meat does not end up on shelves at retail stores.   

Advantages 

è  Existing purchasing systems are used to manage boar taint.   

è  Compliance with specifications is the condition for the supplier to continue selling 
its  meat to  retailers. This  is  a very  strong  incentive  that  may  be  passed  down  to 
processors, slaughterhouses and farmers. 

7.7.1.3  Visits,  information  sharing  and  certification  of  boar  taint  detection 

methods 

In several countries, slaughterhouses and processors have actively provided retailers and 
other clients with detailed information about their boar taint detection methods. This has 
involved: 

-  Full documentation on the protocols put in place for detecting boar taint; 
-  Certification by third party auditors of the boar taint detection protocol in place at 

the slaughterhouse; 

-  On-site visits to demonstrate to representatives of retailers and other buyers the 

efficacy and robustness of the method used. 

Case study: COOPERL’s transition to entire males 

In France, COOPERL has organised numerous visits for retailer and B2B representatives to 
inspect the full process, and especially the human nose method, to convince them of its 
reliability for detecting boar tainted carcasses. The human nose method at COOPERL has 
also  been  audited  and  certified  annually  by  the  German  company  SGS,  which  provides 
additional reassurance to the rest of the supply chain. Further details on the COOPERL case 
study are provided in Section 5.1.1.  

Advantages 

è  Transparency and demonstration of the checks help dispel distrust and build trust 

in the detection method and within the supply chain. 

7.7.1.4  In-store trials 

Retailers  and  food  service  operators  can  gain  additional  confidence  in  the  feasibility  of 
selling meat from entire males by running controlled trials in tight collaboration with their 

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suppliers. Such trials can involve an initial test period during which all the pig meat offered 
is from entire males. Sales and customer complaints are closely monitored during that time 
to identify any issues, and information is shared with the supplier throughout.  

Case study: COOPERL’s transition to entire males 

In France, COOPERL has run trials with store managers, whereby they were informed in 
advance that, for a given period, they would only receive meat from entire males. There 
would be close interaction between a representative of the supplier and the store manager 
during that trial, to monitor any variations in sales and any consumer complaints. Further 
details on the COOPERL case study are provided in Section 5.1.1. 

Advantages 

è  In-store trials can reassure store managers that the provision of meat from entire 
males from a supplier with a robust protocol for boar taint detection does not mean 
adverse impact on consumers and sales. 

7.7.2  Food labelling 

7.7.2.1  Animal welfare labels and other assurance schemes 

A number of animal welfare certification schemes include standards on pig castration. Meat 
can be certified as being compliant with these standards on the basis of third-party audits 
of farms, slaughterhouses, or food processing companies. A label signalling conformity with 
the scheme is then added to the packaging. Such labelling can be relied on by consumers 
as additional information about how the meat was produced and an indicator of quality.  

Various schemes within the EU certify pig meat products. The schemes specify standards 
on  rearing,  housing,  bedding,  the  use  of  antibiotics,  farrowing  crates,  etc.  Some  have 
specific requirements on non-castration, including:  

•  Approximately 95% of  pigs  reared in the UK  are  raised to  Red  Tractor Assured  Food 
Standards  and  approximately  30%  of  these  are  raised  to  'RSPCA'  standards.  Both 
standards  do not allow surgical castration  in the  pork supply  chain. These labels  are 
widely recognised and used by UK consumers. Boar taint may be partially addressed, 
but the labels’ focus is on welfare rather than meat quality.  

•  The reduction of boar taint in the UK is addressed more or less entirely by slaughtering 
boars  at  a  lower  weight.    The  British  Meat  Processors  Association’s  British  Quality 
Assured Pork (BQAP) scheme does not allow for the slaughter of males over 100 kg. 
This is specifically aimed at avoiding boar taint.  

•  The  “Beter  leven  –  Een  ster”  (Live  better  –  One  star)  assurance  scheme  in  the 
Netherlands forbids surgical castration. This standard is applied to pig meat products 
sold in retail markets. Various producers in the Netherlands have developed additional 
animal  welfare  programmes  to  comply  with  the  “Beter  leven”  standard.  The  scheme 
also  requires  producers  to  test  for  boar  taint  and  has  a  detailed  standard  for  these 
tests. 

•  QS  in  Germany  and  IKB  in  the  Netherlands  allow  for  the  production  of  entire  males 
under  their  certification  but  require  that  participating  slaughterhouses  enact 
appropriate boar taint detection methods.   

Advantages 

è  Labelled products can be sold at a higher price than non-assured meat. 

è  Better welfare may be associated with lower boar taint. 

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è  Robust schemes and auditing systems provide additional guarantees to retailers and 
food service operators. Retailers and food service operators can easily require from 
their suppliers that they should be certified compliant with such a scheme. 

Disadvantages 

è  Third party assurance schemes add to the costs of suppliers as they bear the cost 

of audits and the practices specified by the scheme required; 

è  Consumers may associate higher animal welfare with better quality – expect at least 
equal  if  not  better  quality.  There  is  a  risk that consumers  will  be  put off  by  boar 
taint when eating without knowing what it is and will not repurchase. 

Further reading: 

More information on  existing  assurance  schemes,  their requirements  and  approaches  to 
marketing can be found through their official websites:   

•  Red Tractor Assurance official website: https://assurance.redtractor.org.uk/  
•  British Meat Processors Association official website: http://britishmeatindustry.org/our-

work/bmpa-pork-scheme/  

•  Royal  Society  for  the  Prevention  of  Cruelty  to  Animals  Assured  official  website: 

https://www.rspcaassured.org.uk/about-us/  

•  Beter Leven official website [in Dutch]: https://beterleven.dierenbescherming.nl/ 
•  QS official website: https://www.q-s.de/en/  
• 

IKB official website [in Dutch]: http://www.ikbnederland.nl/   

7.8  Q8. Retailers and food services – vaccinated pigs: promoting meat 

from vaccinated pigs  

This  document lists  good  practice  examples  for  the marketing of  meat  from  vaccinated 
pigs, at retail outlets or in the food service sector. The document includes information on 
(i)  how  to  increase  consumer  acceptance  of  meat  from  vaccinated  pigs  and  (ii)  how  to 
prevent meat with detectable boar taint from reaching consumers. The practices mentioned 
are all currently used in commercial operations in the EU.  

Marketing  campaigns  are  used  by  retailers  as  a  technique  to  inform  consumers  about 
animal welfare, health and sustainability aspects of meat production.   

Making the transition to selling meat from vaccinated pigs requires careful consideration 
and planning on the part of the retailer. The following guide refers to practices that may 
be of interest to retailers making such a transition. In addition to the practices described, 
it is important for all retailers to communicate with their suppliers before and during 
any transition to selling meat from vaccinated pigs. Understanding the costs and benefits 
to other parts of the supply chain will also help retailers advocate for and lead the transition 
away from surgical castration. 

Case study: Colruyt’s successful transition to vaccination against boar taint 

In  2010,  Colruyt conducted  a  trial to  improve pigs’  welfare  by using  vaccination  against 
boar taint. It used Improvac on approximately 2,600 boars and monitored all production 
steps  from  vaccination  to  meat  consumption.  Further  details  on  this  case  study  are 
provided in Section 5.3.2. 

7.8.1  Marketing  campaigns  that  emphasise  animal  welfare,  health  and 

sustainability 

Retailers are often reluctant to use the term “immunocastration” in their communications 
to consumers. They therefore opt for using “vaccination” which is more understandable to 
consumers.  Marketing  campaigns  can  combine  information  on  improved  animal  welfare 

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with other benefits achieved with vaccination. This can include, for example, information 
on the improved health of pigs and sustainability.  

Advantages 

è  Marketing meat from vaccinated pigs with ‘better animal welfare’ messages matches 

the growing EU consumer interest in animal welfare.  

è  Consumer  studies  suggests  that,  when  informed  about  vaccination  against  boar 
taint  and  surgical  castration  without  anaesthesia,  consumers  often  prefer  the 
vaccination as this is perceived as more animal-friendly.    

Disadvantages 

è  There is a risk of raising awareness about physical/medical castration, which is not 

desired by retailers as it implies mutilation of pigs.  

è  Communicating about vaccination against boar taint to consumers who have limited 
awareness of this practice poses the risk of misconceptions and misunderstandings. 
Consumers may associate the use of medication with other practices, such as the 
use of hormones in animal production. Furthermore, there may be a risk that media 
amplify consumer concerns.   

Things to consider 

Consumer awareness of alternatives to physical castration may vary across countries and 
consumer  groups.  Although most  consumers  are unaware of castration  practices, others 
may  have  more  knowledge  and  show  more  interest  in  receiving  information  on  these 
practices.  Retailers  may  consider  assessing  the  needs  and  characteristics  of  their 
consumers and adapting their animal welfare campaigns accordingly.  

7.8.2  Farmer management  

Retailers  can  impose  the  vaccination  of  pigs  on  their  pig  meat  suppliers  and  support 
producers with specific training and control measures.    

7.8.2.1 

 Control measures 

The inoculation with the vaccine is often closely monitored at farm level. Retailers and/or 
slaughterhouses  may  choose  to  contract  independent  organisations  to  carry  out  annual 
checks at farms.  

Advantages 

è  Control  measures  guarantee  that  farmers  respect  the  production  requirements 

agreed upon. 

Disadvantages 

è  Retailers may bear the costs of control measures themselves. However, as audits 
are  performed  anyway  there  are  in  general  no  additional  costs  related  to 
vaccination. 

7.8.2.2 

 Training methods 

Animal handlers can be trained on technical aspects regarding vaccine administration and 
treatment of piglets, livestock keeping, and to raise their awareness of animal welfare. This 
is often provided by technical support staff contracted by retailers.   

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Advantages 

è  Training reassures farmers who need to get used to new production practices.  

Disadvantages 

è  Hiring technical  staff  increases  the  costs  for  retailers. However, vaccine  suppliers 
often provide training on the correct use of the vaccine as well. Training costs may 
therefore be distributed among different operators, and not only borne by retailers. 

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8 

Conclusions 

This study has aimed to collect and synthesise information on best practices of pig meat 
production without the use of surgical castration. The information collected will provide a 
basis for communication materials that can be used to encourage more operators across 
supply chains in the EU to abandon the practice of surgical castration and instead move 
towards the production of entire males or males that have been vaccinated. 

Information  on  best  practices  was  collected  from  documentary  sources,  business 
operators, and experts on this subject. A variety of practices and experiences were found, 
including many  examples of  trials  and some  potentially viable  practices  still in the  early 
phases of the development. The final report includes  practices at  farm-,  feed  provider-, 
breeder-, slaughterhouse-, processor- and retailer-level that have been used commercially 
and have been successful.  

While the production of entire males, and even more so, of vaccinated pigs remain small 
in the EU by comparison to the overall production of pig meat, it involves major operators 
that have invested considerable resources, expertise, and effort to find solutions that work 
not  only  within  individual  organisations,  but  across  whole  supply  chains.  Evidence  from 
these  operators  demonstrates that  it  is commercially feasible to transition  from  physical 
castration to raising entire males or vaccinating them against boar taint. 

The  practices  documented  in  this  study  show  that  solutions  require  coordination  and 
information exchange between different actors of the supply chain. Change has happened 
through exchanges of good practices, data sharing, and agreements on how to share the 
costs and the benefits of changes to the mode of production. Successful transitions have 
occurred where initiators have demonstrated to commercial partners that a different way 
of working is feasible, robust, and safe. 

This project has aimed to contribute to this endeavour by extracting information from those 
operators and identifying specific best practices. The format used is meant to be accessible 
and  should  contain  sufficiently  actionable  information  for  other  business  operators 
implement similar practices in their own country and business operations. At farm-level, 
this includes practices related to breeding, housing, feeding and scheduling the slaughter 
of  pigs.  Practices  were  also  identified  specific  to  vaccination  against  boar  taint.  For 
slaughterhouses, practices include human nose techniques to identify boar taint, practices 
that avoid boar taint detection and supply chain management. For vaccination against boar 
taint,  practices  were  identified  that  may  help  slaughterhouses  to  transition  and  develop 
trust in the process. Techniques for processing meat to mask or reduce the impact of boar 
taint are identified as a method to retain the value in tainted meat. Finally, some examples 
of practices at retail level were found which offer an opportunity to add value to meat from 
entire males or vaccinated pigs for consumers.  

Together,  these  individual  practices  provide  a  compelling  portfolio  of  options  for  supply 
chains interested in making a transition away from surgical castration. Crucially, however, 
none of these practices are sufficient in isolation. For any transition to be successful, it will 
need to involve actors from across the supply chain working together. The study research 
identified many such examples of cooperation between actors. To that end, several case 
study examples of successful transitions have also been included in the report. The cases 
on Delhaize and Lidl in Belgium provide examples of retailer-driven transitions, the case 
on  QS  and  IKB  in  the  Netherlands  shows  how  assurance  schemes  can  contribute  to  a 
transition  and  the  case  on  Cooperl  in  France  shows  how  the  transition  can  occur  when 
production and processing supply chains are already integrated.    

Gaps and obstacles remain. Some have to do with limitations in the study, which did not 
manage to extract as much information from some sectors of the industry as would have 
been desirable, and particularly within processing and retail/food services. Other gaps are 
due to many promising techniques still being under development and not yet commercially 
available, particularly techniques for the chemical detection of boar taint. They also reflect 

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the  relatively  poor  degree  of  engagement  from  certain  actors  in  the  supply  chain,  and 
retailers in particular, in this mode of production.  

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Annexes 

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Annex 1 Terms of reference 

Context/Introduction 

Background of the initiative 

This study will aim at supporting the improvement of the welfare of animals. 

The  European  Parliament  adopted  as  part  of  the  Union's  budget  2017  a  pilot  project 
entitled: Establishment of a harmonised internal  market for pigmeat obtained from  pigs 
that have not been surgically castrated. 

This pilot project is accompanied with the following budgetary remarks: 

As  shown  by  the  results  of  the  latest  special  Eurobarometer  on  animal  welfare,  an 
overwhelming  majority  of  European  citizens  care  deeply  for  the  welfare  of  farmed 
animals  and  believe  that  they  should  be  better  protected.  The  surgical  castration  of 
young  piglets  without  pain  relief  is  a  common  and  increasingly  controversial  pig 
management  practice,  currently  affecting 63 million  animals  every year.  Yet  practical 
experience from major pork supply chains within the European Union shows that viable 
and profitable alternatives to surgical castration exist. The pilot project will bring major 
stakeholders together – slaughterhouses, food processors and retailers, and involving 
farmers as needed – and foster the sharing and dissemination of techniques and best 
practices that eliminate the need to castrate pigs surgically. Emphasis will be given to 
knowledge  transfer  activities  concerning  (a)  reliable  and  viable  boar  taint  detection 
methods, (b) utilisation of boar- tainted carcasses during processing, and (c) marketing 
and promotion of meat from pigs that are not surgically castrated. Trust building and 
exchange of information among all market participants in a peer-to-peer environment 
will  be  an important  communication  activity.  The  project  will  deliver  a  practice-based 
guidance  document  paving  the  way  for  a  harmonised  internal  market  for  pigmeat 
obtained from animals that are not surgically castrated. 

The European Declaration on Alternatives to Surgical Castration of Pigs is a voluntary 
and  stakeholder-  driven agreement to  phase out surgical  castration  of  pigs  by  2018. 
The  declaration  was  signed  by  33  parties  representing  European  farmers,  the  meat 
industry,  retailers,  scientists,  veterinarians  and  animal  welfare  NGOs.  While  some 
member  states  have  taken  concrete  initiatives  to  this  end,  there  is  currently  no 
harmonised  internal  market  for  pig  meat  obtained  from  pigs  that  have  not  been 
surgically castrated. This is hindering the progress of the Declaration. The pilot project 
will  accelerate  the  process  by  providing  and  disseminating  practical  solutions  to 
commonly  perceived  problems  among  key  operators  of  the  pork  chain,  while  also 
showcasing  the  associated  economic  and  societal  advantages  of  ending  the  surgical 
castration of pigs. 

Objectives of the initiative 

The project will be implemented in two phases: 

-  The first phase will consist in collecting information on best available practices 
at  various  level  of  the  food  chain  to  market  meat  from  uncastrated  or 
immunocastrated pigs; 

-  The second phase will consist in disseminating the information collected during 
the first phase to raise awareness and transfer best practices among the relevant 
business operators. 

-  The present call only refers to the first phase of the pilot project. 

Specifications of the assignment 

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Objectives of the study 

The present study implies data gathering on different stages of the pork chain and for two 
types of meat obtained either from: 

1.  uncastrated pigs, or, 

2.  immuno-castrated pigs. 

 As regards meat from uncastrated pigs, the objective of the study is to collect information 
on how  farmers  reduce  boar taint, how  slaughterhouses  detect  boar taint,  estimate the 
amount of carcasses with detectable boar taint, how the industry and food processors use 
these carcasses (i.e. with detectable boar taint) and how retailers market the meat from 
these animals. 

As  regards  meat  from  immuno-castrated  pigs,  the  objective  of  the  study  is  to  collect 
information on how farmers perform immuno-castration and how retailers market the meat 
from these animals. 

The purpose of study is to collect successful experiences within commercial contexts. With 
this purpose in mind, best practices collected should be, when possible, science based, but 
should not contain recommendations solely based on research. 

The  study  shall  propose  a  series  of  technical,  organisational  and  marketing  tools  and 
practices  that  could  be  used  by  business  operators  to  successfully  market  meat  from 
uncastrated or immuno-castrated pigs, including the meat with detectable boar taint. 

The study shall include a series of case studies based on the Member States where such 
policies have been implemented, which are at least Germany, France, Spain, Belgium, the 
Netherlands and Denmark. 

The contract will consist in the following steps: 

-  collecting information on current practices regarding the issues to be addressed, 

-  analysing and comparing the sources of information, 

-  proposing a toolbox for the various target audiences. 

The progress and the final results of the study will be reported to stakeholders through a 
dedicated  web  platform  and  two  meetings  of  an  advisory  board  consisting  of  business 
operators  concerned,  representatives  of  the  civil  society,  consumer  associations  and 
scientists. 

The final document will be designed to be read by business operators and organised in a 
way that it will be easy to use for the second phase of the pilot project (dissemination). 

Scope and issues 

The scope and issues of the study are described under Table 10. 

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Table 10.  Issues to be addressed 

Target audiences 

Meat from uncastrated pigs 

Meat from immuno-castrated pigs 

Farmers 

Q1- Techniques and best practices to reduce 
boar taint through management techniques 
(including feeding and breeding) 

Q2- Techniques and best practices to use 
immuno-castration in various type of pigs 
Q3- Techniques and best practices to ensure to 
slaughterhouses that immuno-castrated pigs do no 
present detectable boar taint 

Slaughterhouse 
operators 

Q4- Techniques and best practices to detect 
boar taint, quantify and manage positive 
carcasses 

Q5- Techniques and best practices to trust farmers 
that immuno-castrated pigs do not contain 
detectable boar taint 

Food processors 

Q6- Techniques and best practices to 
quantify and deal with meat with detectable 
boar taint 

Not relevant 

Retail and food 
services 

Q7- Techniques and best practices to 
increase the market value of meat from 
uncastrated pigs and to prevent meat with 
detectable boar taint to be on the shelves or 
served 

Q8- Techniques and best practices to increase the 
acceptance of meat from immuno-castrated pigs 
among consumers and to prevent meat with 
detectable boar taint to be on the shelves or served 

The contractor is expected to collect information for each issue from at least the following 
six  Member  States,  Germany,  France,  Spain,  Belgium,  the  Netherlands  and  Denmark, 
reflecting the diversity in terms of size, geographical distribution and types of production 
and, when considered altogether, covering a significant proportion of the pig meat market. 

Tasks under the assignment 

The Commission expects the contractor to perform the following tasks: 

Task 1: Update of methodology and work plan 

On the basis of the discussions and conclusions of the kick-off meeting the contractor will 
establish an updated general work plan and methodology in order to meet the objectives 
and address all issues. 

Deliverable 1: Updated methodology and work plan 

The deliverable will contain in details the methodology, the timeframe, the final list of 
experts and the organisations to be consulted during the whole study. This document 
should serve as a monitoring tool of the study during the contract. 

Task 2: Collecting data 

The contractor will collect data based on desk research as well as by contacting experts in 
various Member States and preliminary visits in some Member States. 

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This task will mainly consist in collecting information on current good practices relevant to 
the issues to be addressed in Table 10. 

Deliverable 2: State of play 

This deliverable will contain a synthesis of the current state of knowledge on all issues 
to be addressed based on key references and a comparative analysis of the range of 
methods used  by  the  different  sources. The  deliverable  will  also  identify the  gaps in 
information for each subject matter. 

Task 3: Drafting elements for best practices 

Based on the previous findings, the contractor will draft a set of possible techniques and 
best practices (later called "elements for best practices"). The elements for best practices 
should reflect existing practices performed under commercial conditions. 

The document should address the key issues accompanied with relevant explanations on 
the  possible  options  ("toolbox"),  their  advantages/disadvantages.  The  contractor  will 
establish a gradation between various elements proposed depending on their feasibility in 
the various contexts observed in the EU including some quantitative data, such as: 

-  For Q4 the expected percentage of detectable boar taint carcasses compared to 

the number of uncastrated boars, 

-  For Q5 the expected risk of price reduction for farmers in case of detectable boar 

taint carcasses, 

-  For Q6 the percentage of detected boar taint meat compared to the quantity of 
meat they received, and the way such tainted meat can be used or marketed. 

- 
-  The contractor is invited to present the best practices following a structure that 
reflects  the  target  audiences  (i.e.  farmers,  slaughterhouses,  meat  processors, 
retailers and food services) and the meat concerned (meat from uncastrated pigs 
and immuno-castrated pigs, including with detectable boar taint in both cases) 
so that each of the eight issues is addressed extensively. 

- 
-  The  contractor  will  take  a  particular  attention  in  drafting  the  document  in  a 
simple  and  concise  way  (for  non-specialised  reader),  putting  priority  to  visual 
supports (pictures, diagrams, and drawings) rather than text when possible. 

- 

Deliverable 3: Elements for best practices for consultation 

This deliverable will contain the elements for best practices covering all issues to be 
addressed. 

Task 4: Consulting stakeholders on the elements for best practices 

The  contractor  will  present,  discuss  and  finalise  the  elements  of  best  practices  with  the 
relevant  stakeholders.  The  contractor  shall  ensure  at  least  a  minimum  period  of 
consultation of eight weeks. 

For  that  purpose,  the  contractor  will  establish  an  interactive  web  platform  where  draft 
documents  will  be  shared  to  the  stakeholders  consulted  and  where  they  can  provide 
comments  and  contributions  directly  online  with  a  secure  access.  Comments  and 
contributions will be only shared with the consultees who registered in the web platform. 

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The  contractor  will  administer  and  moderate  the  web  platform.  The  comments  and 
contributions  will  be  analysed  and  the  synthesis  should  feed  into  the  elements  for  best 
practices (Deliverable 4). The web platform does not need to be used or transferred beyond 
the duration of the contract. 

In addition, the contractor will organise at least two meetings in Brussels of an advisory 
board consisting of the relevant business operators concerned, representatives of the civil 
society  and  scientists.  This  board  shall  be  set  up  in  agreement  with  the  European 
Commission  with  a  maximum  of  25  members.  The  contractor  will  only  bear  the  costs 
related to the meeting itself. Travel and accommodation expenses of the participants will 
not be reimbursed. 

The  contractor  will  also  ensure  that  the  interests  of  small  undertakings,  having  local 
activities is also taken into account. 

The contractor will consider the comments received from stakeholders and Member States, 
and  after  critical  analysis,  possibly  amend  the draft  documents,  where  contributions  are 
substantiated by factual arguments or/and a broad consensus of opinions. 

Deliverable 4: Consultation and final elements for best practices 

The deliverable will contain a summary of the consultation process and of the 
position of stakeholders consulted, presenting possible conflicts of opinions, the pros 
and cons of each option and a suggested line in case of various alternatives. 

In addition the deliverable will present the final version of the elements of best 
practices in order to reflect the consultation and the opinion of the stakeholders 
consulted (Deliverable 3 revised). 

Methodology 

The  contractor  will  have  a  free  choice  as  to  the  methods  used  to  gather  and  analyse 
information and for making the assessment, but must take account of the following: 

-  The study must be based on recognised techniques and triangulation methods 

are required. 

-  The choice and a detailed description of the methodology must form part of the 
offer submitted. Advantages, limitations and risks involved in using the proposed 
tools and techniques should be explained. There should be a clear link between 
the study questions addressed and the corresponding methodology proposed. 

-  Considerable emphasis should be placed on the analysis phase of the study. In 
addressing the study questions / issues, quantitative indicators should be sought 
and  used  as  far  as  possible.  The  contractor  must  support  findings  and 
conclusions64  by  explaining  the  degree  to  which  these  are  based  on  opinion, 
analysis and objectively verifiable evidence. Where opinion is the main source, 
the degree of consensus and the steps taken to test the opinion should be given. 

-  The approach proposed by the contractor must be clearly set out in the bid. It 

should clearly identify 

a)  data to be collected 

b)  consultation strategy (if applicable) 

c)  Analysis to be conducted. 

64 In some specific cases the contractor might also be requested to formulate recommendations. 

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As an indication stakeholders will be consulted following these different levels: 

3.  Stakeholders in some Member States; 

4.  EU stakeholders; 

5.  Member States' competent authorities; 

6.  Scientific institutes. 

To perform its tasks the contractor will consider the references listed in Section 6. 

Reporting and deliverables 

General reporting requirements 

The present assignment includes the submission of  a series  of deliverables: reports and 
presentations during  a meeting in Brussels (3 meetings). The contractor will  deliver the 
following  reports  at  four  key  stages  of  the  evaluation  process:  (1)  inception  report,  (2) 
interim report, (3) draft final report and final report. 

The contractor must deliver the  study  and all publishable  deliverables in full compliance 
with  the  corporate  visual  identity  of  the  European  Commission,  by  applying  the  graphic 
rules set out in the European Commission's Visual Identity Manual, including its logo. The 
graphic 
at: 
http://ec.europa.eu/dgs/communication/services/visual_identity/index_en.htm 

the  Manual 

information 

available 

further 

rules, 

and 

are 

These reports will be submitted by the Commission to the established steering group, which 
may ask for complementary information or propose adjustments in order to redirect the 
work  as  necessary.  Each  draft  report  will  be  orally  presented  in  Brussels  to  the 
Commission's steering group within 30 days after delivery. 

Each report should be written in English, and critically assessed as it provides the basis for 
tracking the quality of the work done by the evaluator. Reports must be approved by the 
Commission. With work progressing and in the light of new findings, revisions of reports 
already approved may be necessary. 

It is essential that all the reports must be clear, concise, unambiguous and comprehensive. 
They  should  also  be  understandable  for  non-specialists.  The  presentation  of  the  texts, 
tables and graphs has to be clear and complete and correspond to commonly recognised 
standards  for  studies  to  be  published.  A  structured  and  precise  elaboration  of  add-ons 
based on  previous deliverables at every stage of the process  is requested (for  example, 
this could be done via colour-coding parts of the report developed at the offer, inception, 
interim and draft final stage). 

The maximum size65 of each report to be provided is (excluding annexes): 

- 

- 

Inception report: up to 20 pages; 

Interim report: up to 100 pages 

-  Final report: up to 150 pages 

In the average, the text addressing each of the eight issues should not exceed 10 pages, 
i.e.  overall  section  addressing  the  issues  shall  not  exceed  80  pages,  the  rest  being 
dedicated to methodology and consultation. Deliverables that do not respect these limits 
will not be considered. The final report may exceed these limits only after explicit request 
from the Commission. 

65 Under this chapter a page shall not exceed 1500 characters without footnotes. 

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The  reports  must  be  provided  to  the  Commission  in  both  MS-Word  and  Adobe  Acrobat 
(PDF)  format  with  the  charts  in  Excel  (other  formats  may  be  added).  They  must  be 
accompanied, where requested, by appropriate annexes and delivered in accordance with 
the deadlines and requirements set out in the terms of reference and confirmed in the kick-
off meeting. 

Reports must be designed as to respect the protection of private data so that they can be 
published or made available to the public without having to request any prior authorisation 
(see Annex V). 

Each  report  (except  the  final  version  of  the  final  report)  should  have  an  introductory 
page providing an overview and orientation of the report. It should describe what parts of 
the  document,  on  the  one  hand,  have  been  carried  over  from  previous  reports  or  been 
recycled from other documents, and on the other hand, represent progress of the study 
work with reference to the work plan. 

All reports must be drafted in English and submitted according to the timetable defined in 
section 5.3 to the contracting authority. Electronic files must be provided in Microsoft ® 
Word for Windows format. Additionally, besides Word, the final report must be delivered 
in Adobe ® Acrobat pdf format and in three hard copies. 

Inception report 

After signature of the contract, the contractor will participate as soon as possible in a kick-
off meeting with the  steering  group to  present  and  discuss  Deliverable 1.  The report 
should  describe  how  the  methodology  proposed  by  the  Contractor  is  going  to  be 
implemented in  detail,  after  e.g. having  further  examined the  sources of secondary  and 
primary data that  will be used  for the study.  The  report shall not  exceed the number of 
pages mentioned in the 4.1 section. 

Interim report 

The report is to be produced after the desk and field research has been completed, and 
should, to the extent possible, include some preliminary conclusions. The report must as a 
minimum provide: 

  This report will contain an  updated version of Deliverables 1 (work plan), 2 

(state of play) and 3 (draft for consultation) including: 

An overview of the status of the study project; 

A description of problems encountered and solutions found; 

A summary of initial findings and results of the data gathering; 

An assessment of the data, whether it meets expectations and will provide a sound 
basis for responding to the study questions; 

A  conclusion  whether  any  changes  are  required  to  the  work  plan,  or  any  other 
solutions should be sought in order to ensure that the required results of the study 
are achieved. If any such issues are to be identified, they must be discussed in the 
meeting with the steering group dedicated to this report; 

A  proposal  for  the  final  structure of  the  final  report,  as  well  as  a  structure of the 
Executive Summary. 

-  The report shall not exceed the number of pages mentioned in the 4.1 section. 

Draft Final Report 

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This document shall deliver the results of all tasks covered by these terms of reference, 
and must be clear enough for any potential reader to understand. 

It must contain an updated version of Deliverables 1 (work plan), 2 (state of play), 4 
(consultation process and final best practices in English). 

The structure of the report should follow a broad classification into the following parts: 

  Main report: The main report shall present, in full, the results of the analyses and 
conclusions arising from the study. It must also contain a description of the subject 
evaluated,  the  context  of  the  study,  and  the  methodology  used  (including  an 
analysis of its strengths and weaknesses). 

  Annexes: These must collate the technical details of the study, and must include 
questionnaire  templates,  interview  guides,  any  additional  tables  or  graphics,  and 
references and sources. 

  The report shall not exceed the number of pages mentioned in the 4.1 section. 

Final Report 

The  final  report  follows  the  same  format  as  the  draft  final  report.  Furthermore,  it  is 
accompanied by an executive summary (synthesis of analyses and conclusions), of no 
more  than  15  pages.  Each  of  the  eight  issues  (Q1  to  Q8)  will  be  addressed  within  a 
maximum of one page. 

The  executive  summary  summarises  the  study’s  main  conclusions,  the  main  evidence 
supporting them and the recommendations arising from them. After being agreed with the 
Commission  Services,  it  should  be  translated  into  English  and  French  by  a  certified 
professional translation agency. 

The document must take into account the feedback from the steering group on the draft 
final report, insofar as these do not interfere with the autonomy of the contractor in respect 
of the conclusions they have reached and the recommendations made. 

The contracting authority will publish the final report, the executive summary, the abstract, 
the annexes on the Commission's central website. 

In  view  of  its  publication,  the  final  report  by  the  contractors  must  be  of  high  editorial 
quality. In cases where the contractor does not manage to produce a final report of high 
editorial quality within the timeframe defined by the contract, the contracting authority can 
decide to have the final report professionally edited at the expense of the contractor (e.g. 
deduction of these costs from the final payment)." 

The  contractor  will  establish  robust  means  to  ensure  the  reliability,  validity,  and 
comparability of the information collected as well of its analysis and of its reporting. 

The  Commission's shall  assess the  quality of the  final report on the basis of  the quality 
assessment criteria defined in annex VI. 

Progress Reports 

No  progress  reports  are  required  but  any  delay  in  delivery  of  the  reports  or  major 
difficulties  shall  be  reported  to  the  Commission  as  well  as  possible  options  to  mitigate 
them. 

Organisation, timetable and budget 

Organisation 

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The  contract  will  be  managed  by  Unit  G2  –  Animal  welfare  sector  of  the  European 
Commission's Directorate-General for Health and Food Safety. 

Meetings 

It  is  expected  that  the  contractor  participates  in  three  meetings  in  Brussels  with  the 
steering group/official in charge. For these meetings, minutes should be drafted by the 
contractor, to be agreed among the participants. 

Timetable 

The starting date is the date on which both parties have signed the specific contract. The 
period of execution of the contract is eight months. 

The following outline work plan and indicative timetable are envisaged: 

Reports 

Presentation 
Brussels 

in 

Deliverables 

Payments 

Kick-off  meeting 
and 
inception report 
Interim report 

Draft final report 

Final report 

Yes 

Yes 

Yes 

No 

Deliverable 1 

No 

Deliverables 1+2+3 

Deliverables 1+2+4 

Yes 

No 

Draft 
approved 

final 

report 

Yes 

Month 
after 
signature 
1 

4 

7 

8 

Budget 

The estimated maximum budget for the study of the action, covering all the results to be 
achieved  by  the  contractor  as  listed  above,  is  within  the  band  EUR  150.000  to  EUR 
200.000. 

Tenders exceeding this estimated maximum budget shall be automatically rejected. 

Award formula 

The weighting of the award formula shall be 40/60 whereby price shall count for 40% and 
quality for 60%. 

score 
tender X 

for 

= 

cheapest price 
price of tender X 

*  100 

* 

40 % 

+ 

total  quality  score (out  of  100)  for  all 
award criteria of tender X 

* 

60 % 

References 

Basic documents 

  Commission activities 

  http://ec.europa.eu/food/animals/welfare/practice/farm/pigs/castration_alternatives_e

n 

  Study/questionnaire 

FVE: 

http://porcinehealthmanagement.biomedcentral.com/articles/10.1186/s40813-016-
0046-x. 

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  EU  COSTS  Project:  Innovative  approaches  in  pork  production  with  entire  males: 

http://www.cost.eu/COST_Actions/ca/CA15215 

Documents and information to be provided after contract signature (not 
exhaustive) 

  List of possible stakeholders and contacts 

Requirements 

Resources 

The  contractor  shall  ensure  that  experts  are  adequately  supported  and  equipped.  In 
particular, sufficient administrative, secretarial and interpreting resources, as well as junior 
experts,  must  be  available  to  enable  senior  experts  to  concentrate  on  their  core  study 
tasks. 

One member of the team must demonstrate work experience of at least four years at EU 
level  in  drafting  of  best  practices,  performing  stakeholders'  consultation  and  having 
knowledge on animal welfare issues related to the sectors covered by the scope. 

The members of the team will be constituted of at least two experts with at least four years 
of scientific or technical experience in the welfare of pigs in order to analyse and sort the 
information collected. 

Absence of conflict of interests 

The contractor shall ensure that both their organisation and the individual experts proposed 
for this study are not in a situation of conflict of interest regarding this specific assignment, 
and shall include a declaration of absence of conflict of interest (Annex IV) as part of their 
offer. 

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Annex 2 Data collection protocol  

The purpose of this task is to collect information on best practices regarding production, 
the processing and the marketing of meat from uncastrated or immunocastrated 
pigs.  

Scope:  practices  need  to  be  implemented  in  commercial  settings:  there  should  be 
evidence  that  at  least  one  food  operator  (farmer,  slaughterhouse,  processor,  or 
retailer/food  service)  is  using  the  practice  for  its  commercial  operations.  The  target 
stakeholder  groups  and issues to  be  addressed  by  data collection  are listed  in the  table 
below: 

[Table to be tailored for each country, as some issues are not relevant to all countries] 

Target audiences  Meat from uncastrated pigs 

Meat from immune-castrated pigs 

Farmers 

Q1- Techniques and best practices to reduce 
boar taint through management techniques 
(including feeding and breeding) 

Slaughterhouse 
operators 

Q4- Techniques and best practices to detect 
boar taint, quantify and manage positive 
carcasses  

Q2- Techniques and best practices to use 
immunocastration in various type of pigs  
Q3- Techniques and best practices to ensure to 
slaughterhouses that immunocastrated pigs do 
no present detectable boar taint  
Q5- Techniques and best practices to trust 
farmers that immunocastrated pigs do not 
contain detectable boar taint  

Food processors 

Q6- Techniques and best practices to quantify 
and deal with meat with detectable boar taint  

Not relevant 

Retail and food 
services 

Q7- Techniques and best practices to increase 
the market value of meat from uncastrated pigs 
and to prevent meat with detectable boar taint 
to be on the shelves or served. 

Q8- Techniques and best practices to increase 
the acceptance of meat from immunocastrated 
pigs among consumers and to prevent meat 
with detectable boar taint to be on the shelves 
or served. 

More details of the areas to be investigated for each of these questions is provided in the 
data collection form. 

Types  of  information  sources:  information  sources  may  be  of  different  types.  It  is 
expected that most information will be provided by businesses / individuals on the phone 
or through emails. It may  also include websites,  reports,  guides,  quality standards,  and 
training material. Please reference all materials found in the data extraction forms.   

Forms  –  please  summarise the information  found in  the  data  collection  forms  provided 
separately. Please complete all the forms electronically; do not print them. 

Modus operandi 

Desk research – report all sources you are aware of, or are able to identify through 
your own research online; Secure copies of the material you reference in the data 
collection form, either digital or physical copies.  

Consultation of country experts and stakeholders – a representation letter from the 
European  Commission  is  provided  separately,  and  can  be  used  when  contacting 
stakeholders.  

When contacting stakeholders, consider relying on your professional network or that of the 
study team. This will increase the likelihood that information of good quality is sent back 
by stakeholders. 

Field visit – with the Project Manager’s agreement, a good/best practice may be 
witnessed in the field 

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Annex 3 List of presumptive good practices to be included in the data 

collection template 

Stakeholder 
group 

Farmers 

Question 

Areas to be explored 

Q1 - Meat from uncastrated 
pigs: Techniques and best 
practices to reduce boar 
taint through management 
techniques (including 
feeding and breeding) 

Feeding 

  Chicory root 
  Potato starch 
  Tanin extract 
  Pueraria lobate (kudzu root) 
  Non-nutritive adsorptive materials 
  Rye 

Flooring and housing 

  Floor types 
  Temperature 
  Density 
  Cleanliness 
  Enrichment 
  Sex separation during rearing 

Breeding 

  Use of specific low-taint breeds 

(such as Pietrain) 

  Use of new techniques developed 

by breeding organisations 

Early detection 

  Use of behavioural or physical 

characteristics to predict boar taint 
on-farm 

Organisation of slaughter operations 

  Selection for slaughter at a young 

age 

  Selection for slaughter at a specific 

weight 

Posology and administration of 
vaccine 

  Use of three injections for larger 

pigs 

  Administration techniques for 

heavier animals 

Equipment for large-scale 
vaccination 

Q2 - Techniques and best 
practices to use 
immunocastration in 
various type of pigs 

Q3 - Techniques and best 
practices to ensure to 
slaughterhouses that 
immunocastrated pigs do 

Checking that immunocastration has 
worked (on farm)  

  Use of physiological indicators 

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not present detectable boar 
taint 

  Use of behavioural indicators 

Supply chain assurance 

Slaughterhouse 
operators 

Q4 - Techniques and best 
practices to detect boar 
taint, quantify and manage 
positive carcasses 

Food 
processors 

Q5 - Techniques and best 
practices to trust farmers 
that immunocastrated pigs 
do not contain detectable 
boar taint 

Q6 - Techniques and best 
practices to quantify and 
deal with meat with 
detectable boar taint 

114 

  Recognition of immunocastration by 

certification schemes 

On-line assessment (large 
slaughterhouses) 

  On-line chemical detection 

techniques 

  Colorimetric method to measure 

skatole equivalent 
  PTR-TOF-MS technique 
  Other fast GCMS techniques 
  Human nose method 
  Hot iron 
  Hot fans 
  Pyropen/open flame 

Off-line assessment (small 
slaughterhouses) 

  Human nose method 
  Microwave 
  Hot water method 
  Soldering iron 

Consistency 

  Smell test and training for 

assessors 

  Techniques to avoid smell 

habituation  

 
  Quantification of positive 

carcasses 

  Image capturing technologies 
  Pig classification systems 

Management of positive carcasses 

  Systems for monitoring complaints 
  Identification of markets for boar 

meat 

Quality control techniques 

  Sample testing 
  Systems for monitoring complaints 

Dealing with meat with detectable 
boar taint 

  Curing 
  Smoking 
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  Use of spices / masks 
  Techniques to strip fat from meat 
  Use in PDO products 
  Injection of brine 
  Fermentation 
  Thermal treatment 

Retail and food 
services 

Q7 - Techniques and best 
practices to increase the 
market value of meat from 
uncastrated pigs and to 
prevent meat with 
detectable boar taint to be 
on the shelves or served 

Marketing techniques 

Food labelling 

Supply chain audits 

Buyer checks 

Supplier requirements 

  Requiring all pork suppliers to raise 

entire males 

Q8 - Techniques and best 
practices to increase the 
acceptance of meat from 
immunocastrated pigs 
among consumers and to 
prevent meat with 
detectable boar taint to be 
on the shelves or served 

Content of communication to 
consumers 

Communication tools 

Supply chain audits 

Buyer checks 

Supplier requirements 

  Requiring all pork suppliers to use 

immunocastration 

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Annex 4 Model for the data collection template 

Draft data recording template – an example for Q1: techniques and best practices to reduce 
boar  taint  through  management  techniques  (feeding,  breeding  and  organisation  of 
slaughter  operations).  The  actual  data  collection  template  is  in  the  form  of  an  excel 
spreadsheet. 

Area 

Feeding 

Presumptive best practice description 

Diet option 1 

Source 

Farm association (phone call on XX/XX/2017) 

Additional documentation received by email 
on XX/XX/2017 

Evidence of use in commercial 
operations 

Confirmed use in XX, number of farms known 
to use this diet: … 

Quality of the evidence: … 

Rationale for qualifying the practice as 
“best” 

Evidence on boar taint prevalence in entire 
males fed this diet: … 

Quality of the evidence: … 

Source of the evidence: … 

Other relevant evidence: … 

Area 

Breeding 

Presumptive best practice description 

Genetic selection procedure 1 

Source 

Individual expert in pig breeding, called on 
XX/XX/2017 

Evidence of use in commercial 
operations 

One confirmed case in … 

Quality of the evidence: … 

Rationale for qualifying the practice as 
“best” 

Evidence on boar taint prevalence in pigs 
selected: … 

Quality of the evidence: … 

Source of the evidence: … 

Other relevant evidence: … 

Area 

Organisation  of slaughter operations 

Presumptive best practice description 

Slaughter of males under XX months of age 

Source 

Report title …. Published … 

Evidence of use in commercial 
operations 

Confirmed use in country Y, number of farms 
known to schedule slaughter at that age: … 

Quality of the evidence: … 

Rationale for qualifying the practice as 
“best” 

Evidence on boar taint prevalence in entire 
males at the time of slaughter: … 

Quality of the evidence: … 

Source of the evidence: … 

Other relevant evidence: … 

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Annex 5 Consultation – Feedback received from the European Commission and through the online platform 

Table 11.  Cross-cutting 

Comment 

In term of the structure of the chapter, I would rather group 
Questions addressed to farmers (Q1 to 3) then to slaughterhouses 
and food processors (Q4 to 6) and then retailers (Q7 and 8). 

To keep the logic, you should first introduce Deliverable 3 in general 
before going to specific, explaining the general structure of the text. 

Quantitative data is lacking for some practices, e.g.: data is lacking 
on the quantification of positive carcasses (Q4) and meat with 
detectable boar taint (Q6). The report should better explain the 
reasons for these gaps.  

ICF response 

An introductory statement was added and the structure of the 
section was rearranged. 

The “State of play” section of the report has been revised to clearly 
identify data gaps, and the reasons why data was not available. 

A way to simplify the title might be to make some short title like: Q1 
Farms/uncastrated pigs /management techniques;  

The titles have been simplified. 

Q2 Farms/immunocastrated pigs/vaccination; 

Q3Farms/ immunocastrated pigs/detection of pigs not properly 
vaccinated; 

Q4 Slaughterhouses/uncastrated pigs/Detection of boar taint; 

Q5 Slaughterhouses/immunocastrated pigs/Detection of pigs not 
properly vaccintated; 

Q6 Slaughterhouses/uncastrated pigs/use of positive carcases;  

Q7Retailers/uncastrated pigs/promoting meat; 

Q8 Retailers/immunocastrated pigs/promoting meat. 

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[Regarding the disclaimer] This is fine but use of editing to make it 
more visible. I wonder if we should not also put this disclaimer at 
the back of the cover page. 

Disclaimer highlighted by using bold text 

The further reading section is a good idea but unfortunately very 
rare while the text in many instances of this section remains 
relatively general. More details might conflict with the conciseness of 
the text. However, since the purpose of best practices is to give the 
reader the opportunity to change his/her practices, you should 
provide more specific and detailed references possibly in a well 
organised annex (i.e. by topics as presented in the text). This is 
definitively missing in the report. 

An annex including sources organised by topic area has been 
included. 

You may find attached the 4 documents with my suggested changes 
in red; the most important is trying to prevent the use of 
“immunocastration” for broader audiences, because general public 
confuses with chemical castration, and the word castration still 
seems the mutilation of the pig, which is not the case. 

We think is fair to explain what it truly is: immunization (or 
vaccination) against GnRF, which results in suppression of sexual 
activity and consequent boar taint in males. 

Text revised – although some references to immunocastration have 
been kept, as this is also commonly used as a term referring to the 
vaccination 

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Table 12.  Q1 - Techniques and best practices to reduce boar taint through management techniques (including feeding and breeding) 

Comment 

Relevant topic  ICF response 

I have different remarks about the paragraph 1.5 on Commercial feed designed 
to reduce boar taint. Firstly, the product mentioned (called TAINTSTOP) is 
based on three main nutritional pillars: the use of fibers which allows to 
decrease skatole production of the hindgut microbiota by influencing the 
fermentation pattern, the use of natural additives which support the 
metabolism of the animal and an optimal balance between dietary protein 
parameters and specific fiber fractions. Therefore, TAINTSTOP is a feeding 
concept more advanced than chicory alone. 

Feeding – 
commercial feed 
designed to 
reduce boar taint  

No additional details on TAINTSTOP 
have been added, however the section 
does mention that TAINTSTOP combines 
many different feeding techniques to 
address boar taint.  

Secondly, this product is really efficient because it reduces highly significantly 
skatole levels (0% of samples with TAINTSTOP feeding are above the cut-off 
level of sensorial detection) and it decreases numerically androstenone 
quantities. Moreover, it has to be given to boars just 2 weeks before slaughter. 

Thirdly, about the cost, it can be more relevant to compare the production cost 
between castrated pigs fed normally and boars fed with TAINTSTOP than only 
to compare the cost of feeding. Indeed, TAINTSTOP enables an additional 
revenue with a better carcass value, a better feed conversion index, a saving of 
anaesthetic and veterinary costs, time savings, and a saving on manure costs. 
There is also an additional feed cost for 2,2kg intake/pig/day for 14 days but 
the breeder can still expect a net profit per boar compared to castrated pig. 

Finally, there are other advantages with this commercial feed: it obviates 
castration and injection or manipulation on the pig, it improves animal welfare, 
it reduces the preventive use of antibiotics, it reduces nitrogen emissions in the 
environment and it enables to share a positive message for the consumer. 

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Breeding, 
Feeding, 
Scheduling of 
slaughter 

A reference to a shortened period for 
chicory use has been added.  

No mention was included of using 
biopsies for breeding as this does not 
appear to be used in commercial 
practice yet.  

Remarks. New Danish results have shown that feeding a diet with chicory for 3 
or 4 days has the same effect in reducing skatole as feeding for 2 weeks. This 
reduces the feed cost remarkably. Further feeding pure grain for 3 days has 
given a significant reduction in skatole around 50%, which is even cheaper. 
Jerusalem artichoke is also efficient in reducing skatole but not realistic to add 
to commercial diets (at the moment). No effect is seen on the level of 
androstenone. 
http://svineproduktion.dk/publikationer/kilder/lu_medd/2015/1055  (so far 
only in Danish). 

Just published Danish results has shown that selection of fathers with a low 
level of androstenone measured in biopsies from the neck can reduce the 
androstenone level remarkably. There were no effect on skatole. 
http://svineproduktion.dk/publikationer/kilder/lu_medd/2018/1138  (so far 
only in Danish). 

The level of androstenone increases linear with the weight from 60 to 120 kg 
liveweight. Results from a trial where biopsies were taken on the same male 
pig with an interval of 10 kg. 
http://svineproduktion.dk/publikationer/kilder/lu_medd/2017/1102  (so far 
only in Danish). All results have been presented at meetings in IPEMA.  

I have 3 remarks – breeding: it is possible to select boars with lower boar taint 
within a breed with the oestradiol level from a blood sample (Prunier and al., 
2016) - sex separated rearing is not recommended for sanitary reasons due to 
over mixing piglets. By comparing mixing and separated rearing we have no 
effect on boar taint level if pigs are reared with good practices - it is more 
important to talk about slaughter age than slaughter weight to manage the 
boar taint  

Breeding, Early 
detection, 
Flooring and 
housing, 
Scheduling of 
slaughter  

Regarding breeding: This has not been 
included as selection based on blood 
samples does not appear to be a 
commercially-used practice at present.  

Regarding sex-separation: ICF’s 
understanding is that different farmers 
have had very different experiences 
with sex separation and it is common 
practice in some countries but not 
others. The practice remained included 
in the drafts, but the differences in 
experiences were emphasised.  

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Regarding slaughter age/weight: 
Selection based on weight has been 
removed from the drafts as a best 
practice, although the use of weight cut 
offs will still be discussed.  

I believe strongly in the possibility to lower boar taint levels by breeding and 
selection. It is possible to lower boar taint levels in all breeding lines of a 
breeding program, without harming economical genetic progress in general. It 
already implemented in specific breeding programs. generation by generations 
levels go down already. Also it is possible to sort boars on base of breeding 
values for boar taint levels to create special terminal boars to produce progeny 
with lower boar taint levels. This system is available and was proven it works. 
The problem in the market is that there is no incentive for producers to apply 
these special breeding lines (higher price for semen), because slaughter houses 
do not pay a bonus for low boar taint or put a penalty on high boar taint. If a 
bonus.malus system is implemented in slaughterhouses for boartaint the 
producers will start using boar taint low breeds and lines and we will move into 
the direction of lower boartaint. So implement a bonus system in 
slaughterhouses will be the best way to motivate the producers and breeding 
can solve the problem. Also this will stimulate the change of management on 
the farms with too high level to adapt hygiene and feed regimes etc. 

Breeding, 
Bonus/Malus (Q4) 

More details have been added regarding 
options for practices related to 
breeding. 

In addition to breeding, this comment 
also points to the need for cross-supply 
chain analysis. This is being addressed 
in the State of Play section of this 
report.  

Under section 2.4, the following text is included: 

Low stress environments 

Good practices include: 

Low stress 
environments 

- Keeping a low animal density (recommendations differ depending on pig 
weight: at least 0.75 m2 per pig for pigs between 85 and 110 kg; at least 1 m2 
for pigs above 110 kg). 

- Ensuring temperature control and proper ventilation. 

- Keeping pigs clean and dry. 

This has been revised to reflect that the 
figures provided only indicate the legal 
minimum. A more qualitative indicator 
has been included in the text regarding 
space allowances.  

Information on enrichment has also 
been revised, based on input from this 
comment and previous guidance 
published by the European Commission.  

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- Providing enrichment, such as: balls on chains, hanging plastic pipes, wood 
and branches, straw in racks or as bedding. Enrichment objects that are 
destructible, edible and encourage rooting are most effective. This helps keeps 
boars calm and occupied.  

The space allowance quoted in the first bullet point for pigs over 110kg is the 
minimum required under EU legislation. Therefore, it is difficult to see how this 
can be described as 'good practice'. 'Good practice' should go above and 
beyond the basic minimum. 

The examples of enrichment suggested includes balls on chains and hanging 
plastic pipes. Whilst the paragraph goes on to say that enrichment objects that 
are destructible, edible and encourage rooting are best, including these non-
destructible and non-edible materials appears to give credence to their use as 
acceptable materials. In addition, the Commission itself states that, in addition 
to being destructible and edible, materials should specifically also be 
'investigable' and 'manipulable', categorising materials according to how many 
of these criteria a material fulfils.  Under the Commission's own guidance and 
recommendations, these items would be classed as 'items of marginal interest' 
and should not be considered as fulfilling a pigs essential needs and therefore 
'optimal' or 'sub-optimal materials' should also be provided where these are 
used. It would be useful to expand on these issues in this paragraph. 

I attached to this email a grafic of the different protein needs of boars and 
gilts. 

Feeding, flooring 
and housing 

That is why you need different feed to get the best results. 

And it is also profitable to keep boars and gilts separate so you can give them a 
different diet. 

We made a flyer in The Netherlands about the behaviour of boars. 

I attached both documents. 

With this project we wanted to describe the best practices. 

More information on protein needs and 
boar behaviour from the leaflet provided 
has been included in the guidelines.  

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So it would be useful for other countries, slaughterhouses and farmers to use 
this information. 

I do not see this back in all the papers you have written at the moment.  

It is not about science but about using science in practice.  

It is a pity that you don’t describe some cases. For instance the case of Cooperl 
in France from farmer to consumer, the case of VION in The Netherlands etc. 

Then you get a more integrated view that can be used by other parties. 

[On feeding protein-reduced diets four days before slaughter] To the best of 
my knowledge this is a research result from Hanne Maribo, and not a best 
practice, unless you have results from commercial farms that do use this 
already for a longer period. 

Feeding – 
protein-reduced 
diets 

This practice received positive feedback 
during the Advisory Board meeting and 
appears to be used in practice.  

[On low protein diets leading to a slower growth rate] Already within four days?  

Disadvantages related to this practice 
have been removed from the final 
version. 

[On feeding with adjusted amino acids] Do we have farms with experience on 
this as a best practice? 

Feeding – 
adjusted amino 
acids 

Yes, ICF found evidence of this being 
used in practice. It is also recommended 
in guidelines produced by Wageningen.  

[On commercial feed] Do they sell it to many farms, with the costs mentioned 
below? 

Feeding – 
commercial feed 
designed to 
reduce boar taint 

It is not clear how many farms this is 
sold to, but it is commercially available 
and we received evidence of it being 
used. As the feed is only provided in the 
period immediately before slaughter, 
additional costs only apply to that 
period.  

Do not mention fully slatted floors, it is forbidden and therefore not a best 
practice 

Slatted floors 

Slatted floors has been removed as a 
practice and included within a section 
on ‘Keeping pigs clean and dry’. 

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I would state that dry floors keep pigs clean and dry [as opposed to slatted 
floors, under Advantages] 

[Regarding differing evidence for sex-separated rearing] This is correct: some 
report on this as a best practice and others just the other way round. 

Sex-separated 
rearing 

The variety of experiences related to 
sex-separated rearing has been 
elaborated on in the text.  

Also smaller group size: large groups have higher risks 

Low-stress 
environments 

This has been added to practices under 
‘Low-stress environments’. 

[Regarding reference provided] This information is so old: why did you not take 
a look at the annual report of Topigs Norsvin in which they report on the 
realized reduction in boar taint prevalence with genetic measures: the report is 
on the internet. 

Breeding, 
scheduling of 
slaughter 

We want to know about recent best practices, and not about what a researcher 
did write almost ten years ago 

References to studies have been 
removed from the final document. 
Where appropriate, these have been 
replaced with references to existing 
guidance or to examples of where 
transitions have already occurred. 

This whole section has hardly to do with best practices. This is all theory that is 
not applied in practice. 

Scheduling of 
slaughter 

[Regarding differentiating between quick and slow growers] This has nothing to 
do with boars.  

Selection for 
slaughter at a 
specific weight 

We do this also with castrates. 

124 

The scheduling of slaughter section has 
been amended to focus on slaughtering 
by a certain age, and discussing the 
various issues related to this, based on 
discussions at the Advisory Board 
Meeting.  

This section has been removed from the 
draft.  

 
 
 
 
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Do slaughter companies not mention more on this? Temperature, ease of 
handling, …. ? 

Transport to the 
slaughterhouse 

[On further reading] We are not interested in many issues but in the few best 
practices that work 

Transport to the 
slaughterhouse 

[On Civic Consulting resource] This report has nothing to do with best practices 

The section on transport has been 
removed from the final version of the 
best practices due to insufficient 
evidence on how transport impacts on 
boar taint  

The section on transport has been 
removed from the final version of the 
best practices due to insufficient 
evidence on how transport impacts on 
boar taint  

When referring to feed, be more specific and provide the latin name of the 
plant as well as the way it is used (which forms?) 

Chicory root 

The Latin name has been included in the 
text. 

Again this is too vague to be practically useful see previous comment. 

Protein-reduced 
diet 

Additional details have been added to 
the text. 

Again too vague. Good teaser but what do I do if I want to try this "best 
practice"? 

Diet adjusted for 
amino acids 

Additional details have been added to 
the text. 

Again vague, please provide brands or feed manufacturers names… 

Again a bit too vague; Which Member States? 

Commercial feed 
designed to 
reduce boar taint 

Brand names have been added to the 
text. 

Slatted floors 

References to specific Member States 
have been added. 

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[Regarding practicality] What do you mean? 

Sex-separated 
rearing 

Further explanation has been added in 
the text. 

This is not low density, it is the minimum requirement of the pig directive… 
Check with Directive 2008/120/EC 

Low-stress 
environments 

This section has been amended to 
indicate that the recommended figures 
are legal requirements and has provided 
a more qualitative indicator for ensuring 
pigs have enough space.  

Again lack of references while there a detailed Commission Recommendation + 
staff working document + various educational materials produced by the 
Commission!! See 

https://ec.europa.eu/food/animals/welfare/practice/farm/pigs/tail-docking_en 

Low-stress 
environments 

This reference has been included in the 
text. 

Any practical template to implement this method, (check list, etc.) 

Early detection 

[Regarding “Farmers should regularly look for these signs and take decisions 
accordingly”] Be more specific. 

Early detection 

[Regarding “farmers may choose to slaughter pigs before a certain age.”] This 
is very very unprecise !! 

Selection for 
slaughter at a 
young age 

126 

Early detection has been removed from 
the draft as stakeholders indicated 
during the Advisory Board Meeting that 
this was not a feasible practice for 
entire males.  

Early detection has been removed from 
the draft as stakeholders indicated 
during the Advisory Board Meeting that 
this was not a feasible practice for 
entire males. 

Decisions about scheduling for slaughter 
may be constrained by market 
requirements: for example, certain 
slaughterhouses may require a certain 
weight range for commercial reasons. 
These requirements may differ across 

 
 
 
 
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[Regarding “Switching from an open system to a closed one may require 
significant resources.”] Not very clear what is an open system and why this 
may require significant resources. Which ones? 

Transport to the 
slaughterhouse 

This disadvantage has been removed 
from the final version following review 
by a team expert.  

slaughtering plants. These observations 
limit the possibility to include precise 
ages at slaughter that would be broadly 
applicable in the EU pig industry. These 
limitations have been clarified in the 
text of the document. 

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Table 13.  Q2 - Techniques and best practices to use immunocastration in various type of pigs 

Comment 

Weight gain with Improvac. 

Relevant topic  ICF response 

Weight gain and 
improvac 

This is frequently quoted as a positive side effect or consequence which for the 
product of fresh pork would be a potential benefit. However, for larger or heavy 
weight pigs used to produce Continental Charcuterie (e.g Parma Ham, min 
165kg slaughter weight & 9 months age); this would be a negative as 
potentially the legs would be too lean (insufficient fat) to meet the 
requirements of the Parma Ham PDO.  

From the research we have conducted in Italy with Improvac for Parma Pigs we 
were often using 4 vaccinations; experienced health issues with the animals at 
the vaccination site in the neck and had to adapt diet to slow the growth of the 
animal. 

A completed protocol with number of vaccinations and adapted diet that 
produces equivalent raw material to that of castrates has yet to be completed 
and trial work continues. 

There are some challenges with the effectiveness of immune-castration and 
specific breeds of males in preventing sexual development and taint. We have 
seen poor results when researching immune-castration with both Iberico males 
and Calabrian black pig. We have also been advised that immune-castration is 
not as effective with Duroc breed. 

Immunocastratio
n & genetics 

128 

The issues have also been confirmed by 
ham producers. The 4 vaccinations 
protocol therefore cannot be considered 
a best practice.  

Additional evidence was requested from 
the consultee but was not received. 
Other evidence gathered for this study, 
and feedback from other consultees 
suggest that the main issue associated 
with immunocastration is the potential 
incorrect administration of the vaccine, 
rather than the pig’s breed. Therefore 
these observations have not been 
included in the best practice documents. 

 
 
 
 
 
 
 
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The documentation makes no reference to replacing spraying of Iberico gilts 
(free range system) and use of immune-castration. We have demonstrated that 
immune-castration can be used for Iberico gilts. 

Gilts and 
immunocastration 

The study focusses on male pigs; 
castration of gilts is outside of the scope 
of the practices. 

Vaccination 
process 

Text revised – the wording “vaccination 
(against boar taint)” has been used 
throughout 

Edits to text indicated in red: 

The vaccine may be administered by farmers, or by others (such as external 
vaccinators trained and certified by vaccine suppliers), depending on the 
preferences and commercial arrangements of each farm. The vaccination 
requires the injection of two doses, occurring at different times of the pig’s life. 
The first injection is done as early as eight weeks of age and has no 
physiological effect; the second should be given at least four weeks after the 
first. The second injection should occur within four to ten weeks before 
slaughter as the effect needs sufficient time to develop and is temporary, 
waning over time. 

The substances responsible for boar taint (mostly androstenone and skatole) 
decrease significantly two to three weeks after the second dose. Meat from 
vaccinated pigs can be safely eaten at any time after the vaccination, as the 
approved withdrawal time is zero days. 

An additional injection might be applied if pigs are observed to be non properly 
immunized (for example, if the size of the testes remains unchanged, or there 
is boar behavior)1. At the begining, farmers usually give a third dose to 3 or 
4% of the pigs.When farms are well experienced and confident with the use of 
the vaccine, and staffreceive regular training on vaccination, the proportion 
requiring a third dose may be as low as 0.3% of pigs. 

… Farmers may adapt the timeline according to their needs (for example, based 
on specific characteristics of their production process, or according to 
slaughterhouses’ requirements on market weights). 

… 

It is injected subcutaneously under the skin behind the pig’s ear (see picture 
below: the red mark indicates the correct site where the vaccine should be 

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injected). The person administering the vaccine should calmly enter the 
animal’s pen and inject the dose with a special dosing gun (see below). 

…  

The preparation, maintenance and cleaning of the special vaccination syringe; 

The vaccine reduces pigs’ aggressiveness towards other pigs, which happens as 
they sexually mature during the finishing phase. Farmers may choose to 
vaccinate pigs as to benefit from these positive behavioural effects in 
comparison with the production of entire boars. …  

Advantages 

(cid:0)Vaccination minimises undesirable pig behaviour, such as mounting and 
aggressiveness. This is beneficial to animal welfare and may also improve 
carcass quality. 

Disadvantages 

(cid:0)The time between the second dose of the vaccine and the slaughter should 
not exceed 10 weeks; if this happens, a new dose of the vaccine should be 
administered 4 to 10 weeks before slaughter to secure absence of boar taint in 
carcasses. 

Some farmers choose to administer the first dose as late as possible, to reduce 
the chance of individual animals not being treated. The interval between doses 
should be at least 4 weeks, and pigs should be slaughtered between 4 and 10 
weeks after the second dose. 

Early vaccination  Text revised as suggested, with the 
exception of text on the comparison 
with non-castration (as comparison 
between merits of immunocastration 
and non-castration are out of the scope 
of the documents) 

Late vaccination  Wording revised as suggested 

Disadvantages 

If the technique is not properly executed, there may be animal welfare 
concerns, such as stress and risk of abscesses associated with the additional 
vaccination 

Use of three 
injections for 
larger pigs 

Wording revised as suggested 

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Before the second dose of the vaccine against GnRF, pigs are fed the same way 
as entire males. … 

For example, the average quantity of feed eaten daily by common breeds of 
pigs may be increased by 20% after the second dose. On a daily basis, this 
results in a weight gain approximately 5% higher than entire males. 

Advantages 

(cid:0)Vaccinated pigs grow faster and reach their slaughtering weight earlier than 
entire males. Overall, this can result in less time for vaccinated pigs to reach 
the market weight (not affecting their feed efficiency as the grow fast). 

The vaccine against GnRF can have the same effects in humans as in pigs. For 
this reason, it is necessary to avoid the risk of accidental self-injection. A 
special syringe (also called dosing gun – see picture below) should be used to 
administer the vaccine. This tool has a several safety mechanisms: the needle 
is protected, and it is only activated once the gun is pressed against the pig's 
body and the trigger is pulled. 

Feeding of 
immunocastrated 
pigs 

Text revised; the wording “vaccination 
(against boar taint)” has been used 
throughout 

Dosing gun 

Wording revised as suggested 

"The second injection should not occur within four to five weeks of slaughter as 
the effect needs sufficient time to develop." the above highlighted statement is 
not correct. The second vaccination should occur 4 to 6 weeks prior to 
slaughter and pigs should be send to slaughter latest 10 weeks after second 
vaccination or else be given a third vaccination (eg Parma or Iberico 
production). The European regulatory authorities have approved this 
vaccination schedule based on a significant dataset resulting from pivotal 
scientific studies. Maybe the statement is only a typo and should read ‘ the 
second injection should occur withing four to five weeks of slaughter…’ In that 
case, there is only a small incorrection in that the registration dossier stipulates 
4 to 6 weeks prior to slaughter instead of 4 to 5 weeks. This should also be 
corrected in the drawing of the schedule. The drawing is otherwise correct.  

Vaccination 
process 

Timeline revised as suggested, also 
consistently with feedback provided by 
vaccine suppliers 

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"On average, between 3% and 4% of pigs may need a third dose. When farms 
are well experienced with the use of the vaccine and staff receive regular 
training on vaccination, the proportion of pigs requiring a third dose may be as 
low as 0.3% of pigs." This is an important statement and explains the 
confusion about so called ‘non-responders’: animals given both doses of 
vaccine correctly respond in virtually 100% of cases as is substantiated by a 
large volume of published studies. Therefore, in virtually all the cases in which 
animals do not respond, it is not due to the application of the vaccine, but 
rather due to the ‘non-application’ of the vaccine, and this explains the need for 
adequate training of the vaccine-administrators and explains why good 
administration combined with good certification (documentation) can ensure 
the slaughterhouses and retail of non-tainted pork product. 

Vaccination 
process 

These observations have been further 
emphasised in the best practice 
documents. 

Early vaccination  The text has been revised as suggested.  

"With early vaccination there is an increased risk of individual animals not 
being treated as they are smaller at the time of the first vaccine and it may be 
more difficult to differentiate between piglets which have been vaccinated and 
those which still have to receive their dose. Some carcasses may therefore 
present boar taint." This is not correct: the system of vaccination of younger 
pigs is exactly the same as for older pigs. The vaccinated pigs receive a colour 
mark to distinguish them from the non vaccinated pigs. The only difference is 
that the smaller piglets have more space to run around, so you may have to 
use a handling board as is described higher, and you may have to ‘bend your 
back’ a little more to reach them, but vaccination should only start when the 
pigs have stopped running and group together in one side of the pen so that 
they can easily be reached. When done properly, there is no difference in 
accuracy between first and second vaccination. 

"Some farmers choose to administer the first dose as late as possible, to 
reduce the chance of individual animals not being treated." This is not a correct 
argument for later first vaccinations. There is a lot of flexibility for the timing of 
the first vaccination, so farmers can choose to vaccinate earlier or later 
depending on their time management. (The first vaccination only primes the 

Late vaccination  Text revised as suggested. 

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immune system, and does not have any other physiological effect.) I will 
elaborate on advantages and disadvantage of later or earlier vaccination below 

"Late vaccination may help ensuring that an increased proportion of pigs are 
correctly vaccinated" This is not correct (any data to substantiate this 
statement?) Examples for relevant advantages for late first vaccinations are: if 
piglets had to travel long distance between the nursery house and the fattening 
site, it is better to let them rest for a week and reduce their stress levels before 
starting to vaccinate. Another reason can be to streamline work-efficiency and 
have the first vaccination of a new batch fall at the same day of the second 
vaccination of an earlier batch. 

Late vaccination  Text revised as suggested. 

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Table 14.  Q3 - Techniques and best practices to ensure to slaughterhouses that immunocastrated pigs do not present detectable boar 

taint 

Comment 

[Regarding “pig species”] Breeds? 

[Regarding figure] Always provide a title to the picture and a numbering 
system like Figure x – visual assessment of the testes 

Regarding the drawing: provide picture of pigs with an ENTIRE tail since routine 
tail docking is prohibited by the EU legislation. 

Visual 
assessment of 
testes 

This document provides good practice examples that can be used by farmers to 
provide slaughterhouses assurance that pigs immunized or vaccinated to 
prevent boar taint do not present detectable boar taint. … Farmers may inspect 
pigs on-farm, before sending them to the slaughterhouse, to verify whether the 
vaccination protocol was administered correctly. Additionally, it is good practice 
for farmers to keep records of vaccination and control procedures. Farmers 
may share this information with slaughterhouses to demonstrate that they are 
following the right quality assurance procedures. 

Introduction 

Figure 1. Example of potential testes’ size reduction as a result of vaccination  Visual 

assessment of 
testes 

134 

Relevant topic  ICF response 

Visual 
assessment of 
testes 

This practice was considered by 
stakeholders to be ineffective at 
identifying at-risk pigs and will be 
removed from the final version.  

This practice was considered by 
stakeholders to be ineffective at 
identifying at-risk pigs and was 
removed from the best practice 
documents. 

Text revised; the wording “vaccination 
(against boar taint)” has been used 
throughout 

This practice was considered by 
stakeholders to be ineffective at 
identifying at-risk pigs and was 
removed from the best practice 
documents. 

 
 
 
 
 
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Farmers may include information on the QA of vaccination process in their 
standard pig transport documentation, to share with slaughterhouses. … 
Farmers may add the following details on vaccination: 

Documentation  Text revised; the wording “vaccination 

(against boar taint)” has been used 
throughout 

(cid:0)The number of immunized males; and 

(cid:0)A confirmation that vaccinated pigs have been checked prior to slaughter, 
and that farmers have identified pigs which are suspected to present boar taint 
(if any). 

Farmers may wish to share with slaughterhouses an additional document 
(vaccination declaration), with details on the vaccination process: 

… 

(cid:0)The number of immunized pigs sent for slaughter. 

A sample template for the vaccination declaration is presented below.  

Figure3.Example of a template for the vaccination declaration 

Documentation on vaccination is generally paper-based. … It is also possible to 
transmit data on vaccination procedures followed with an electronic system. 
This system can be accessed in real time by several people, including those 
responsible for the administration of the vaccine, the farmer, the vaccine 
supplier, and the slaughterhouse staff. This system simplifies the tracking and 
verification of proper vaccination data. 

… 

The vaccination declaration enables to identify the person who administered 
the vaccine.  

“Sexual behaviour may sometimes be confused with dominance behaviour: to 
establish a hierarchy in a group, for example, some pigs may try to mount 
other pigs. Dominance mounting is shorter and less frequent than sexual 
mounting. 

135 

A statement has been added to the best 
practice doc that this becomes a routine 
task when trained. 

 
 
 
 
 
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Dominance behaviour does not necessarily indicate that the pig has not been 
correctly vaccinated.” 

remark: this is correct, but as is stated, the trained eye can make the 
difference between dominance behaviour and sexual behaviour. Farmers are 
with the pigs every day and are even required by European legislation to 
observe their pigs on a daily basis. When trained for the signs, it becomes a 
routine job to identify pigs that may have missed a dose. 

“The reduction in testes size may vary across pigs and pig species; this may 
make it more difficult to correctly identify pigs who may have not been 
correctly vaccinated. For example, the size reduction in Iberian-Duroc cross-
bred pigs is higher and more homogeneous than in white pigs.” 

remark: an important sign and more reliable indicator than the ‘size of the 
testes’ is the size of the epididymis. This organ is empty of active spermatozoa 
and therefore hardly visible in the vaccinated animal, leaving two ‘cavities’ in 
the scrotal sac. This is a tell-tale for compliantly vaccinated boars. 

Visual assessment of the testes was 
considered by stakeholders to be 
ineffective at identifying at-risk pigs and 
will be removed from the final version. 

A follow-up question was sent to the 
stakeholder regarding evidence of the 
commercial use of epididymis checks.  

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Table 15.  Q4 - Techniques and best practices to detect boar taint, quantify and manage positive carcasses 

Comment 

Relevant topic  ICF response 

DMRI has developed an analytical method that can be used to analyse skatole 
and androstenone on a small fat biopsy taken from the carcass. The method 
uses laser diode thermal desorption mass spectrometry (LDTD-MS/MS) and is 
in compliance with the EU’s reference laboratory method, which also uses mass 
spectrometry. The newly developed method makes it possible to perform a 
rapid, selective and quantitative analysis. Through further automation of the 
method, equipment installed at a slaughterhouse will be capable of analysing 
up to 2,800 fat samples per day. The same method has been set up in DMRI’s 
laboratories. For further information: boartaint.dk 

On line detection 
techniques 

It does not appear that this technique 
has been used yet in commercial 
practice, and is therefore out of scope.  

It is an error to consider that the carcass weight is an issue to avoid boar taint. 
Depending to the growth rate, there are light carasses (from older pigs) whith 
boar taint. That is better to think about slaughter age by asking to the farmer 
to manage the slaughter age. 

Weight and age 
at slaughter 

Weight appears to be the most 
commonly used threshold by 
stakeholders. This issue will be 
discussed at the stakeholder meeting 
and with experts.  

We have a policy that if an animal is <120kg live weight at slaughter then we 
do not castrate or if castrated as farmers to change to non-castrated. 

Weight and age 
at slaughter 

The document has been edited to reflect 
that age is more important than weight.  

We have a number of farms in Holland where pigs are being finished at 130kg 
and left entire. 

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[Regarding hot water method being used in smaller slaughterhouses] Did you 
interview a slaughter company doing this?  

Hot water method This practice was confirmed by one 

expert and one slaughterhouse.  

If not, do not mention it as a best practice that has been reported to you. 

[Regarding hot water being a validated method] By the retailer?  

[Regarding further reading section] We are talking about best practices that 
have been used in very recent years: Using a leaflet from 2011 is annoying.  

We need experiences from companies, no summing up of old leaflets. 

The reference to validation refers to 
work done by the DMRI. Reference to 
this has been deleted, however, as it is 
unlikely to be understood by the end 
user.  

Hot water method References to studies have been 

removed from the final document. 
Where appropriate, these have been 
replaced with references to existing 
guidance or to examples of where 
transitions have already occurred. 

The section on instrumental methods 
has been removed from the final 
version.  

[On instrumental method being used commercially] I really doubt this: if yes, 
how is it claimed that it is a best practice?  

Instrumental 
methods 

Are we talking here about the old Danish method? What arguments can you 
provide that this is a succesful best practice.  

To the best of myy knowledge it was a complete catastrofic adventure. The 
reason for not becoming accepted was - among others - that it did not include 
androstenone. 

[On penalties] I do not think that there is one single penalty system for boar 
taint prevalence in operation. They charge a premium to the farmer, but 
independent of the boar taint prevalence. 

No penalties 

[On penalties being applied if boar taint indicators exceed a threshold] If you 
do not have a name of a slaughter company applying this successfully, you 
have to delete this. Because in that case it is not a best practice. 

References to the use of penalties have 
been removed from the final version, as 
there is little evidence that this is 
currently being used with success. This 
issue is discussed in further detail within 
the state of play.  

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Larger, smaller or companies independent of size?  

Same-sex groups This was reported by three large 

I would be surprised if larger companies apply this. 

slaughterhouses. 

I do not understand this. 

Classification of 
carcasses 

It is not clear what exactly this 
comment is referring to. 

We do not want literature: we want to know about best practices from 
companies that you have interviewed. All the rest is redundant: please delete! 

Further reading 
section 

References to studies have been 
removed from the final document. 
Where appropriate, these have been 
replaced with references to existing 
guidance or to examples of where 
transitions have already occurred. 

No reference or ways I can find a supplier? 

Hot iron method  Information on suppliers has been 

Provide references again 

added.  

Smell tests and 
training 

References to smell test providers will 
be added in the text. 

[Regarding disadvantages] This point is about no penalty so I do not 
understand this here. Problem of formulation? 

No penalties 

This has been reworded to clarify the 
point.  

[Regarding cost of infrastructure] Quite vague 

Electronic 
classification of 
carcasses 

No specific information was available.  

“No. this is the problem. We do not immediately see a comprehensive, cheap 
and fast method that offers guarantees. The "human nose" method is still 
widely used and does provide a definite answer, but for that you must have 

Detection 
methods 

Human nose is now the only method 
referenced in this document. Since 
other chemical methods are not yet in 

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well-trained people and once a pig with boar taint has been detected, this 
person cannot continue working for some time. 

commercial use, these have not been 
included in the guidance.  

That is why we are also interested in the methods that are under development, 
such as those with "iknife", whereby a chemical analysis can be done online 
very quickly. But to my knowledge, there is not yet a fast and affordable 
method available.” 

Slaughterhouses should consequently sorting out such boars that are behaving 
strongly like sexually matured boars. If signs like heckle, foaming are shown 
and young boars are trying to jump on others these boars should be sorted out 
ideally already in the farm or at least at slaughterhouse lairage area for alive 
animals. 

The biggest influence does have the stadium of puberty. The longer the boars 
are in puberty stadium the higher the risk that boar taint is strong. 

For training and verification of human nose it is helpful to identify a critical limit 
of skatol and androstenon that people have to detect during training. 100% 
solutions of skatol and andostenon are may be smellable by many people. It is 
more interesting to define a minimum concentration that boar taint smellers 
have to identify. This minimum concentartion can be defined by a sensorical 
testing panel where the sensoric penel members define upon which 
concentration boar taint is detectable for a "normal" human being. 

Feedback received from the advisory 
board meeting indicated that it was very 
difficult to use behavioural indicators 
with entire males and that this is 
therefore not a feasible best practice. It 
has been removed from the final 
version.  

For this reason, scheduling of slaughter 
has been amended to focus on age 
rather than weight.  

This is being done by consulting groups 
that offer smell tests and training to 
slaughterhouses. As slaughterhouses do 
not appear to provide their own training 
at present, including further details on 
best practices for smell testing is out of 
scope. 

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Table 16.  Q5 - Techniques and best practices to trust farmers that immunocastrated pigs do not contain detectable boar taint 

Comment 

Relevant topic  ICF response 

[Regarding figure] See previous figure on testes – no tail docked please!! 

Checks based on 
testes 
measurement 

These checks were not considered to be 
good practice by consulted stakeholders 
and were removed from the best 
practice documents. 

Since the gland is internal, does it require a particular care when the carcass is 
cut in half? 

Checks based on 
bulbourethral 
gland 

This relates to butchering and is 
therefore out of scope.  

In order to make decisions based on the size of the testicles, we ask ourselves 
whether this is a reliable method. For some species/breeds vaccination has 
little or no influence at all on the size of the testes. A visual check can often 
give a wrong impression or lead to the wrong decision. 

Furthermore, we ask ourselves whether measuring the testes (in the 
slaughterhouse) is a good method that should be recommended. This will be 
very time-consuming and therefore also quite expensive despite being 
considered as inefficient. 

Checks based on 
testes 
measurement. 

These checks were not considered to be 
good practice by consulted stakeholders 
and will be removed from the drafts. 

This document focusses on the topic of immunization or vaccination against 
GnRF (also called immunological castration) from the perspective of 
slaughterhouses    … 

Introduction 

Text revised; the wording “vaccination 
(against boar taint)” has been used 
throughout 

Many slaughterhouse operators, and their customers, remain sceptical of the 
proposition that vaccination against GnRF is an effective means of preventing 
boar taint. 

Lack of trust in the vaccine as a means of preventing boar taint is an issue 
across the supply chain, from slaughterhouse operators onwards. 

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Consequently, building trust in immunization requires engagement with many 
different actors, from farmers to retailers and consumers. The following 
practices are used to increase confidence in vaccination and its effectiveness. 

Some slaughterhouses choose to conduct random checks for boar taint in 
vaccinated pigs on the slaughter line, using the same techniques that are used 
for entire males. The frequency of checks will depend on the slaughterhouse 
and farmer and their experience with the technology. More frequent checks 
may be necessary for less-experienced slaughterhouses and farmers. The 
person responsible for receiving the animals in the lairage may also check for 
the signs of improper immunization on arrival.    … 

(cid:0)This can be used to enhance industry-wide confidence in the vaccination 
process. 

The vaccine has been shown to significantly reduce the size of the testes. 
Immunized male pigs can be sampled for boar taint based on the size of their 
testes. The testes of all vaccinated pigs are measured on line using callipers. 
Pigs whose testes exceed acertain diameter (e.g. 110 mm) are then targeted 
as suspicious. A fat sample is takenand assessed for boar taint, generally using 
the human nose method off-line. 

The vaccine has been shown to significantly reduce the size of these glands. 
Immunized pigs can be selected for testing based on the size of these glands. 

The staff at the slaughterhouse can take a fat sample from a small number of 
immunocastrated pigs and send these to an external laboratory for chemical 
testing. The samples can be selected based on perceived risk, for example 
through the measurement of testes. This testing is used to detect the levels of 
androstenone (and other compounds) in the fat.        … 

142 

Random checks 
for boar taint 

Text revised; the wording “vaccination 
(against boar taint)” has been used 
throughout 

Checks based on 
testes 
measurement 

The section on checks based on testes 
measurement has been removed as this 
practice was not considered sufficiently 
reliable. 

Checks based on 
bulbourethral 
gland 

The section on checks based on 
bulbourethral gland has been removed 
as this practice was not considered 
difficult to implement and not 
sufficiently reliable. 

Chemical testing 
of a sample 

Text revised; the wording “vaccination 
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This type of testing is only suitable for a small number of carcasses. It will 
likely give an incomplete picture of the level of boar taint in immunized pigs. 
Tainted meat may enter the supply chain as a result. 

(cid:0)This type of testing may be too expensive for some slaughterhouses. If 1 per 
cent of carcasses are tested, this will cost around 0.03 EUR per kilo of meat 
received from vaccinated pigs. 

Farmers should keep documented records of vaccinated pigs. 

Documentation  Text revised. 

Although some slaughterhouses still treat vaccinated pigs as boars and pay less 
for them (as compared to physically castrated pigs), there are other 
slaughterhouses that do not issue penalties or who choose to pay more (for 
example, an extra 0.01 EUR per kg). The price premium for vaccinated pigs is 
made possible by certification schemes and by demand from retailers who are 
interested in selling meat from immunized pigs. 

Bonus payments  Text revised; the wording “vaccination 

(against boar taint)” has been used 
throughout 

Advantages 

(cid:0)Bonus payments increase the profitability of using vaccination for farmers. 

Disadvantages 

(cid:0)Bonus payments rely on slaughterhouses or their customers having increased 
demand for pork from vaccinated pigs. 

"These checks are not based on any specific risk factors and therefore may not 
be efficient." This is not correct. The checks are based on specific factors. Non-
vaccinated pigs behave different (more active, more vocal and more sexual 
aggressive behaviour combined with less feeding and red, large, active 
testicles.) For a stockholder who is trained in looking for these signals, it is not 
difficult to assess them reliably.  

Random checks   Text revised to emphasise the 

importance of carrying out risk-based 
checks. 

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"These checks require that staff receive additional training to properly assess 
testes size." Note: testes size is only one parameter in the assessment. When 
testes size is looked at in combination with the checks on the live animals, a 
higher accuracy is achieved. The bottom line is that, when carcasses come in 
that give reasons for doubting good vaccination compliance, a fat sample can 
be taken as described higher. But the better assessment is on the live animals, 
because at that time corrective management can still be applied (revaccinating 
the pig or marking the pig as an entire boar.) 

Checks based on 
testes 
measurement 

The section on checks based on testes 
measurement has been removed as this 
practice was not considered sufficiently 
reliable. 

Table 17.  Q6 - Techniques and best practices to quantify and deal with meat with detectable boar taint 

Comment 

Relevant topic  ICF response 

Applications for meat from sorted entire male pigs. The meat that is sorted out 
because of boar taint odour and flavour must be used in products in which the 
odour and flavour have been masked. Different possibilities, such as smoke, 
fermentation, process temperature and masking with spices, have been 
investigated. Meat from entire males with higher concentrations of skatole and 
androstenone can generally be used for processed products rather than for 
fresh meat products without consumers reacting negatively to the boar taint 
odour and flavour. It is also an advantage to combine different strategies, such 
as dilution and smoke. For further information: boartaint.dk 

Strategies for 
processing 
tainted meat 

Many of these techniques are already 
included. The use of different strategies 
in combination should be highlighted in 
the report.  

No techniques, only best practices!!! 

Title of section 

The wording used for the titles of 
individual documents has been 
amended.  

Very confusing, is it about boar tainted meat or about meat from immuno 
vaccinated animals? 

Introduction 

This section is about boar tainted meat. 
Revisions to the title make this clear.  

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Not very useful in practice. What percentage in weight? 

Diluting and 
mixing 

It is difficult to set a defined percentage 
as this depends on several different 
factors. This has now been explained 
more thoroughly in the text.  

When providing reference, give the author and full title and not only the link 
since it might change overtime. 

Thermal 
treatment 

References to studies have been 
removed from the final document. 
Where appropriate, these have been 
replaced with references to existing 
guidance or to examples of where 
transitions have already occurred. 

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Table 18.  Q7 - Techniques and best practices to increase the market value of meat from uncastrated pigs and to prevent meat with 

detectable boar taint to be on the shelves or served 

Comment 

Relevant topic  ICF response 

Although this is relevant information, 
this is currently not a practice used 
commercially and is therefore out of 
scope. 

Consumer 
thresholds for 
tainted meat.  

Consumer response and sorting limits. The carcasses are sorted to ensure that 
the consumers do not receive meat that could result in a negative reaction. 
Consumer surveys are conducted in order to be able to set the optimum sorting 
limits. The consumers assess how much they like meat from entire males with 
varying concentrations of skatole and androstenone in the neck fat. There is a 
large variation in the extent to which the consumers like meat from the same 
entire male pig. This could partly be due to differences in our sensitivities to 
skatole and particularly androstenone and also differences in how much or how 
little we like the odour of the compounds. Furthermore, there are geographical 
differences in the extent to which the consumers react to boar taint odour and 
flavour. A European study has shown that Danish consumers are among those 
who react most negatively to skatole and androstenone. ARTICLES: 
Christensen, R., Nielsen, DB., Aaslyng, MD (2019) Food Quality and Preference 
71, 209-216, Estimating the risk of dislike: An industry tool for setting sorting 
limits for boar taint compounds. Aluvé, M., Aaslyng, MD. et al...(2018) Meat 
Science vol 137, side 235-43. Consumer acceptance of minced meat patties 
from boars in four European countries Font-i-Furnols, M., Aaslyng, MD et al... 
(2016) Meat Science vol 121, side 96-103. Russian and Chinese consumers' 
acceptability of boar meat patties depending on their sensitivity to 
androstenone and skatole Aaslyng, MD., Broge, EHL., Brockhoff, PB., Haubo 
Christensen, R. (2016) Meat Science vol 116, side 174-85. The effect of skatole 
and androstenone on consumer response towards fresh pork from m. 
longissimus thoracis et lumborum and m. semimembranosus Aaslyng, MD., 
Broge, EHL., Brockhoff, PB., Haubo Christensen, R. (2015) Meat Science vol 
110, side 52-61. The effect of skatole and androstenone on consumer response 
towards streaky bacon and pork belly roll 

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Welfare labels 

These points have been corrected in the 
text.  

This document states that: 

About 30% of pigs reared in the UK are raised to Red Tractor Assured Food 
Standards1 and 'RSPCA'2 standards that do not allow castration in the pork 
supply chain. These labels are widely recognised and used by UK consumers. 
Boar taint may be partially addressed, but the labels’ focus is on welfare rather 
than meat quality.  

This is incorrect. Approximately 95% of pigs in the UK are reared to Red 
Tractor Assured Food Standards. Approximately 30% of UK pigs are reared to 
RSPCA standards under the RSPCA Assured, higher welfare food label. The 
actual figure for the latter was 27.2% for 2017.  

In addition, for clarification, the RSPCA welfare standards for pigs prohibit 
surgical castration; the use of Improvac is permitted.  Justification, including 
welfare-related reasons, must be given to the RSPCA Farm Animals 
Department in writing and the Department’s written response must be made 
available to Freedom Food assessors and RSPCA Farm Livestock Officers.  

The same paragraph is included in the document titled: Techniques and best 
practices to increase the market value of meat from uncastrated pigs and to 
prevent meat with detectable boar taint to be on the shelves or served. As 
such, it will also need correctly. 

It has been very clear from the beginning that we do not want lists of 
techniques, and only look for best practices 

Entire section 

[Typo in section 1.2] 

Buyer 
specifications 
addressed to 
supplier 

147 

Based on experts’ and consultees’ 
feedback, some practices have been 
removed as not considered best 
practices. 

This has been amended in the text. 

 
 
 
 
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[On better welfare labels] Did you interview Dutch retailers on this? 

That would help making it realistic.  

Talking about Red tractor is talking about something implemented 15 years 
ago. We are not waiting for that. 

[On ‘Beter leven’] This is false information: It certainly does include 
requirements to detect boar taint. 

Delhaize does explictly talk about castration,and to the best of my knowledge 
they do consider it being a succesfull best practice 

[On further reading section] Very old information: do not use literature, and 
limit yourself   to best practices from companies instead of referring to 
marketing leaflets. 

This is all theory: retailers do rarely get complaints, for the reasons you 
mention yourself.  

The question is whether they do analyse pork sales for specific products in 
which the risk of boar taint is quite high?  

In my opinion the only best practice is based on "The proof of the pudding is in 
the eating". And this is very complex because so many factors do influence 
sales. But if you have talked to a retailer who can do this, please let us know. 

Red tractor remains relevant as an 
assurance scheme that does not allow 
castration. A range of assurance 
schemes with policies regarding 
castration and detection have now been 
included, along with links to their 
websites for more information.   

Information on the Beter leven label and 
detection has been amended.  

Consumer 
complaint 
mangement 

This has been removed from the final 
version of the document.  

See previous comment. Be more explicit so that if the link is corrupted or 
changed, we can still find the information. 

Animal welfare 
labels 

All references have been revised 
accordingly. 

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Table 19.  Q8- Techniques and best practices to increase the acceptance of meat from immunocastrated pigs among consumers and to 

prevent meat with detectable boar taint to be on the shelves or served 

Comment 

Relevant topic  ICF response 

"often" means that you have few example when it was done. Could you give 
precise examples? 

Marketing 
campaigns that 
emphasise animal 
welfare 

Specific examples (Aldi, Colruyt) will be 
included in the text.  

In the document "Practises to increase the acceptance of meat from IC pigs 
among consumers..." in section 3.1 "disadvantages", it is not entirely clear to 
me what is meant here. Controls indeed generate additional costs that 
eventually need to be borne by someone, but also for the use of adjusted feed 
or even the use of intact bears the retailer will have to carry out checks to 
assess whether the requested criteria are met. Therefore, I do not consider 
that this method generates extra costs. 

Costs 

The document does not refer to extra 
costs of immunocastration compared to 
costs of growing entire males; they only 
mention that, should retailers wish to 
implement these checks, they may have 
to face the costs of doing these checks. 
Therefore the text has not been revised. 

This document provides good practice examples that can be used by business 
operators to successfully market meat from pigs immunized or vaccinated 
against GnRF, and prevent meat with detectable boar taint reaching 
consumers, whether via retail outlets or the food service sector. 

Introduction 

Text revised; the wording “vaccination 
(against boar taint)” has been used 
throughout 

Marketing campaigns are used by retailers as a marketing technique to foster 
the acceptance of meat from vaccinated pigs among consumers. 

Marketing 
techniques 

Text revised; the wording “vaccination 
(against boar taint)” has been used 
throughout 

Retailers are often reluctant to communicate about vaccination practices to 
consumers. Marketing messages addressed to consumers do not mention the 
fact that the animals are immunologically castrated. Rather, these messages 
generally mention broader better animal welfare standards. Advantages 

Marketing 
campaigns that 
emphasise animal 
welfare 

Text revised; the wording “vaccination 
(against boar taint)” has been used 
throughout  

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(cid:0)Marketing meat from vaccinated pigs with ‘better animal welfare’ messages 
matches the growing EU consumer interest in animal welfare, and avoids other 
practices that still imply mutilation (castration with or wiothout 
anesthesia/analgesia). 

Disadvantages 

(cid:0)There is a risk of raising awareness about physical/medical castration, which 
is not desired by retailers. 

Retailers may choose to train staff to properly respond to consumers’ questions 
related to vaccination raised in stores; this may also include the preparation of 
leaflets with detailed information for highly involved consumers. 

Consumer 
complaint 
management 

Retailers can impose the use of vaccination of pigs on their pig meat suppliers 
and support producers with specific training and control measures. 

Farmer 
management 

The document also refers to consumer 
preference of immunocastration over 
physical castration. 

The section on consumer compliant 
management has been removed as, 
based on stakeholder consultations, this 
practice does not appear to be used 
specifically to address issues associated 
with vaccination. 

Text revised; the wording “vaccination 
(against boar taint)” has been used 
throughout 

Animal handlers can be trained on technical aspects regarding vaccine 
administration and treatment of piglets, livestock keeping, and to raise their 
awareness of animal welfare. This is often provided by technical support staff 
contracted by retailers. The vaccine is a prescription product supervised by 
licensed veterinarians. 

Training methods Text revised; the wording “vaccination 

(against boar taint)” has been used 
throughout 

Advantages 

… 

(cid:0)Veterinarians guarantee the supply of safe and quality pigs for the food chain 

"There is a risk of raising awareness about surgical/medical castration, which is 
not desired by retailers." This is more or less correct. Some retailers (although 
others do like Lidl, Delhaize and Colruyt in Belgium) do not want to focus on 

These retailers have been contacted to 
gather additional information on the 

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the methods used, because consumers are mostly unaware about any 
methods. The message to consumers is to ensure them about improved welfare 
for the animals. But, there are no secrets and full transparency should be given 
to the more inquisitive consumers.  

practices used. Additional information 
has been included in the documents. 

"Hiring technical staff increases the costs for retailers" Costs can be shared in 
many ways. The producer of the immune-castration product has a vested 
interest in training farmers to vaccinate correctly and therefore can absorb 
some of the costs. Also: vaccinating pigs gives a better food conversion and 
therefor gives a financial benefit for the farmers. 

Training methods The text has been revised to specify 
that training is provided by vaccine 
suppliers. 

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Final report 

Annex 6 Consultation – Advisory Board 

This  annex  presents  the  notes  from  the  two  Advisory  Board  meetings.  Notes  were 
circulated to attendants for review, and the version presented here integrates comments 
received. 

First Advisory Board meeting – 12 September 2018, Brussels 

Introduction and objectives 

These notes summarise the outcomes of the first Advisory Board meeting organised by 
DG SANTE and ICF for the Study on “Establishing best practices on the production, the 
processing  and  the  marketing  of  meat  from  uncastrated  or  immunocastrated  pigs”. 
Additional information on the meeting objectives and scope are detailed in the meeting 
presentation provided separately by ICF. The meeting was attended by 13 stakeholder 
representatives, DG SANTE and members of the ICF research team. 

Action points 

After  the  meeting,  ICF  will  follow-up  individually  with  participating  stakeholders  to 
gather additional information on various points raised during the discussion, namely: 

  Practical challenges for farmers associated to implementing immunocastration 
  Additional practices related to assuring immunocastration has been successful  
  Harmonisation of detection schemes in DE and NL 
  Use of immunocastration for the production of Parma ham  
  Research results in Germany related to entire males production 
  Research results on various processing options and their effectiveness 

Next steps 

ICF will revise the draft documents based on feedback and additional evidence received 
during the meeting and through follow-up research.  

A second Advisory Board meeting will be held on 11 October 2018 to: 

  Identify challenges associated with the implementation of the good practices 
  Discuss  the  best  ways  to  further  disseminate  materials  and  achieve  maximum 

impact 

Summary of the meeting 

The meeting began with a round of introductions by the participants and an introduction 
to the pilot project’s context and following activities by DG SANTE. ICF then presented 
a brief introduction to the study, meeting objectives and the methodology.  

The study is the first part of a two-part project. 

This part of the project is meant to collect into a single document a basis of knowledge 
on best practices, presented in the form of a “toolbox” of different options, explaining 
what the options are and their advantages and disadvantages. The document is to be 
structured in eight sections addressing eight questions, and addressed at four distinct 
target audiences: (i) farmers, (ii) slaughterhouses, (iii) food processors, and (iv) retail 
and food services. 

The second part of the study will build on the material collected in the first part, and will 
focus on disseminating the best practices in the form of communication material, and 

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through events.  There is  an  open  call  for  tender  that has  just  been  published on the 
second part.66  

In  the  meeting  the  study  team  has  presented  the  practices  included  in  the  draft 
documents and an open discussion followed.  

Concerns were voiced at different points in the meeting regarding the overall structure 
of the  report.  Some  stakeholders  found  the  use  of  ‘advantages’,  ‘disadvantages’  and 
‘further  reading’  to  be  inadequate.  There  was  a  desire  for  both  more  technical 
information  and  greater  use  of  examples.  ICF  clarified  that  it  was  working  towards 
providing more detail and more actionable information – including names and references 
of providers of equipment, feed, etc. – in the revised documents, based on information 
it  had  collected  and  insights  shared  by  participants  to  the  meeting.  ICF  clarified  also 
that the document is not in itself the guidance that will be provided to target audiences. 
That is to be generated in phase 2 of the project, which has been recently put to tender. 
Instead,  this  report  will  constitute  the  knowledge  base  on  which  guidance  and  other 
communication materials will be elaborated. 

Concerns were also voiced that in their current state the drafts are missing important 
information. ICF clarified that the purpose of the meeting was to identify gaps or errors 
and discuss with participants the most appropriate ways and sources to address those 
gaps before the document is finalized. 

Throughout the discussions, several points were made that were applicable across the 
sections, including:  

  Boar  taint  is  only  one  factor  of  many  and  is  generally  not  the  most  important 
factor that  actors  across the  supply  chain  will pay  attention to. This  should  be 
better acknowledged in the draft documents. Best practices should be identified 
as beneficial for factors other than boar taint (such as welfare, meat quality etc.), 
as long as these practices also result in reduced boar taint. 

•  The document should better reflect the demand driven nature of the sector and 
the  level  of  control  that  actors  further  down  the  supply  chain  –  retailers  in 
particular – hold over the rest of the chain.  

Furthermore, other more general comments also were made that shed a broader light 
on the overall initiative: 

•  There is a cross-cutting need for better communication between members of the 

supply chain and the harmonisation of standards wherever possible. 

•  While at present it is feasible to market meat with detectable boar taint in the 
EU, there are concerns that this may hit a ceiling should the production of entire 
males increase beyond a certain point. 

Below  is  a  summary  of  key  points  raised  in  the  discussion  on  each  of  the  topics 
presented.  

Topic 1: Techniques and best practices at farming level 

Feeding 

(1) In  general,  the  section  on  feeding  was  felt  by  many  to  not  include  enough 
relevant detail. Information on how often boars are fed, whether feed should be 

66 The call for tender is available at: https://etendering.ted.europa.eu/cft/cft-

display.html;eTenderingPublic=ImHX7_9ZI9T9NUnwwtPx64OUTFRaclXcuwgviZgZWroGn3nqOy0L!-
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wet  or  dry  and  how  often  the  feed  is  changed,  for  example,  are  important 
elements for inclusion.   

(2) The  point  was  made  that  although  chicory  root  has  been  shown  to  be  very 

successful, it remains at present too costly. 

(3) Grain-based  diets  (providing  low-protein  feed)  have  been  found  to  reliably 

reduce boar taint by a study in Denmark and are an inexpensive option.  

(4) Concern was raised that no incentive currently exists to adopt particular feeding 
practices at farming level. Payment schemes to encourage the uptake of farm-
level best practices were cited as being extremely important. However no current 
scheme encouraging feeding through payment schemes has been reported. 

(5) The  cost  presented  for  the  price  of  TaintStop  feed  (100/EUR  per  tonne)  was 
questioned. It was pointed out that as this feed is only provided for the 3-4 days 
prior to slaughter, therefore the additional cost incurred is not as significant as 
one  may  think.  Furthermore,  ICF  indicated  that  the  manufacturer  (Dumoulin) 
contributed comments on the draft and has not corrected the price information. 

(6) Reduced  competition  at  feeding  was  noted  as  an  aim  that  can  be  achieved  in 

various ways and that this could be discussed in more detail in the document.  

Housing/flooring 

(1) Group size can be an important factor and is currently not included in the draft 
documents.  Keeping  pigs  in  larger  groups (over  30  pigs) increases the risk of 
boar taint.  

(2) The practice of selecting larger pigs for early slaughter is considered to be poor 
practice  as  it  alters  group  dynamics  and  requires  the  re-establishment  of  a 
hierarchy within the group, leading to increased fights and stress.  

(3) There were differing opinions on the inclusion of slatted floors, given implications 
in terms of costs on the one hand, and animal welfare on the other. A suggestion 
was made to keep the practice to “keep pigs clean and dry” and mention slatted 
floors as an option to achieve that objective.  

(4) No  conclusion  was  reached  on  the  effectiveness  of  sex-separated  rearing  at 
reducing  stress  and  aggressiveness  among  boars.  It  was  established  that 
different practices exist and farmers have experienced differing levels of success.  
It was pointed out, however, that sex-separation is required when pigs are raised 
to heavier weights. It was agreed that this practice should remain included but 
differing experiences should be explained.  

(5) More generally, more information needs to be included on managing boars. This 
is  an  important  aspect  to  ensuring  that  farmers  can  make  the  transition 
effectively. 

Breeding 

(1)  Similarly to many feeding techniques, there is no real incentive for farmers to 
use these methods at present. An example was given of a German company that 
provided a premium to farmers for a year to use low boar taint sperm.  

(2) There is a risk with breeding for boar taint that other elements of the meat quality 
may be impacted by changes to genetics. Examples were given where there were 

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notable losses to quality following breeding experiments. Boar taint is only one 
factor of many and not the most important one.  

(3) There are two main breeding strategies to reduce boar taint: selecting a specific 
breed known for low boar taint (for example, Piétrain), or selecting within a breed 
boars that have low taint, based on a blood test of the animal.  

(4) Topigs Norsvin has successfully developed a method for offering sperm from low-
taint  boars  of  different  breeds.  That  is  commercially  available  but  supply  is 
currently  limited.  Nucleus  in  France  has  developed  a  line  of  Pietrain  boars 
selected for low boar taint (INO Boar) 

Early detection 

(1) Although early detection based on behavioural or physical characteristics is easily 
done for immunocastrated pigs (where the vaccine leads to calmer, less active 
pigs), it is not particularly easy to spot notable differences in entire males.  

Scheduling – age versus weight 

(1) Age is a better predictor of boar taint although there is also a correlation with 
weight. Indeed the most at-risk boars are the slow growers that end up sent to 
slaughter at an older age. As such scheduling for slaughter on the basis of age 
is a better practice than selection on the basis of weight. 

(2) Ear tags were mentioned as a helpful practice for tracking the age of pigs.  

(3) Carcass  weight  standards  differ  between  countries  and  markets.  There  are 
economic incentives that are linked to weight. This is another reason why raising 
to lower weights cannot be qualified as best practice.  

Immunocastration 

(1) The  effectiveness  of 

immunocastration  when 

implemented  correctly  is 
established.  However,  a  comment  was  made  that  the  draft  documents  should 
better  explore  challenges  which  farmers  may  face  when  implementing 
immunocastration. There is an added effort required that needs to be accurately 
recorded in the drafts. 

(2) An example was raised of experience in Italy raising heavy pigs for Parma ham 
using  immunocastration.  This  example  involved  the  use  of  three  vaccinations 
instead of two. This example illustrates that much depends on farm management 
for the successful use of immunocastration, and this needs to be better reflected 
in the documents. 

Transport 

(1) The conditions of transport were highlighted as an important aspect that needs 
to  be  covered  in  the  documents.  Good  conditions  of  transport  from  farm  to 
slaughterhouse  can  contribute  to  reducing  boar  taint,  by  limiting  stress  and 
aggressiveness  in  the  hours  that  precede  slaughter.  This  should  include 
principles for  the  transport  of  boars together in  their  group,  and  in  groups  of 
appropriate size, as well as temperature regulation. 

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Topic 2: Boar taint detection methods along the supply chain  

Detection instruments 

(1) The instrumental system introduced in Denmark is still in use. The human nose 
technique  is  not  considered  to  be  sufficient  by the industry  there.  However,  it 
was noted that there has not been further development in the use of the system 
elsewhere. 

(2) Other instrumental methods are under development, and this appears to be the 
way  forward  for  the  future  but  these  are  not  yet  commercially  available.  The 
point  was  also  made  that  there  have  been  proven  discrepancies  between 
different lab results and that even chemical testing methods are not fool proof. 

(3) At present, the human nose method seems to be the only viable option, although 
there  are  concerns  both  about  its  reliability  and  about  the  relative 
unpleasantness of the job for workers.  

(4) Efforts  have  been  made  to  develop  standardised  and  harmonised  approaches. 
An example was given of the QS scheme in Germany working with an assurance 
scheme  in  the  Netherlands  to  harmonise  detection  methods  across  the  two 
countries.  This  was  felt  to  be  an  important  point  for  inclusion  in  the  report, 
considering  the  broader  objective  of  achieving  coordination  and  mutual 
recognition of techniques across the EU.  

(5) Regarding the selection of boar taint assessors, the point was made that people 
who are highly sensitive (around 1% of the population) should not be used as 
they are more likely to be less accurate due to fatigue.  

(6) Some slaughterhouses use in-house staff to carry out detection, while others use 
external contractors or borrow trained staff from other slaughterhouses. There 
is little difference between large and small slaughterhouses in the use of one as 
compared  to  the  other  option.  Additionally,  the  economic  feasibility  of  using 
human nose techniques does not differ between slaughterhouse sizes. There is 
a fixed cost to setting up such a system. The more important factor is whether 
the  slaughterhouse  processes  enough  boars  for  the  implementation  of  human 
nose procedures to be cost effective. It was noted that only slaughterhouses that 
would  process  boars  on  a  continuous  basis  would  find  this  a  cost-effective 
approach.  

Scales for detecting boar taint 

(1) Both  Yes/No  scales  or  more  granular  (e.g.  1-5)  scales  are  considered  to  be 
effective ways for slaughterhouses to manage tainted carcasses, depending on 
the needs of the slaughterhouse.  

Other practices 

(1) A question was raised about the use of boar free slaughter days and whether this 
is  still  practiced.  One  stakeholder  mentioned  that  certain  slaughterhouses  in 
France have boar-free periods during the day, albeit not whole boar free days.  

(2) Handling of boars on entry to the slaughterhouse was identified as an important 
aspect currently missing from the documents. This is important to reduce stress 
levels,  and  involves  considerations  on  group  handling,  handling  of  aggressive 
animals and lairage conditions. 

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Topic 3: Supply chain dynamics and assurance processes 

(1) The measurement of testes was not  considered  to  be an  adequate method  for 
determining  whether  immunocastrated  pigs  are  at  risk  for  taint.  There  is  too 
much  variation  for  this  to  be  a  usable  technique  and  therefore  it  should  be 
removed from the report.  

(2) A  method  was  described  whereby  blood  samples  are  taken  and  tested  for 
testosterone, as an indicator of boar taint. Testosterone is highly correlated with 
androstenone,  so  this  can  be  used  to  determine  what  pigs  are  at  risk  for 
presenting boar taint.  

(3) The use of the bulbourethral (cowper’s) gland was mentioned as something that 
has been tried, but the gland is comparatively small and risks being destroyed 
when carcasses are cut in half. As such it is not reliable. 

(4) An example was given from Germany where all non-castrated males, including 
immunocastrated pigs (rather than only testing a random or at-risk sample), are 
tested using the human nose.   

(5) The issue was raised that the document at present does not properly present the 

costs and benefits of immunocastration as a whole. 

(6) The  point  was 

that 

raised 

the  advantages  and  disadvantages  of 
immunocastration  or  raising  entire  males  have  a  lot  to  do  with  market 
requirements as these are both ‘special market’ products. As such the feasibility 
of either approach depends on the size of the market and the size of the business 
handling such meat. 

(7)  Having  an  objective  method  for  detecting  boar  taint  and  a  payment  schedule 
that can be based on this is an important prerequisite to incentivising farmers to 
switch  and  to  take  up  preventative  practices  (i.e.  those  in  Topic  1).  However, 
current commercial practices do not provide illustrations of this.  

(8) Records of immunocastration will be included in official medical records in some 

countries that accompany the pigs from farm to slaughterhouse.  

(9) The point was raised that the power to alter the supply chain is with retailers as 
they are the principal buyers, but that at the same time many other parts/pieces 
of meat from a carcass will end up elsewhere, to be processed and/or exported. 
The identification of outlets for the various parts of the carcass is a complex task. 
These  other  customers/markets  may  not  accept  certain  practices,  so 
slaughterhouses  need  to  consider  this  carefully  before  making  the  transition 
towards slaughtering entire males.  

(10) The  example  was  given  of  Cooperl 

the 
transformation/processing part of the supply chain and are therefore better able 
to manage these risks. This suggests that operators that combine slaughtering 
and processing activities are better placed to transition towards the production 
of meat from entire males or immunocastrated pigs than others. Companies such 
as Tönnies or Vion also combine slaughtering and processing activities. 

in  France,  who  own 

Topic 4: Processing practices to quantify and deal with meat with detectable 
boar taint 

(1) There is mixed evidence on some of the processing techniques – there is some 

evidence, for example, that dry curing may be less effective. 

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(2) Cooked products that are not to be re-heated for consumption were identified as 
another option in addition to those already listed in the report. One more option 
was the cooking of large batches of tainted meat in an open cooking system. 

(3) The discussion of processing also raised the issue of changes to aspects of the 
meat  quality,  such  as  the  quantity  of  fat,  which  can  make  processing  more 
challenging.  

(4) Exporting to countries or markets with ‘low sensitivity’ was considered to be a 
poor solution because it is not clear that such markets actually lack sensitivity to 
boar taint. One example was given of a market (Russia) that at some point was 
a large importer of products made with tainted meat.  

(5) Use of boar tainted meat as pet food was not considered an appropriate option, 
given  that  the  objectives  of  the  initiative  are  to  provide  meat  for  human 
consumption  and  enhance the  prospects of  producers  to sell meat  from  entire 
males or immunocastrated pigs to consumers. 

(6) Boar  taint  is  a  relatively  minor  quality  issue  at  the  processing  stage.  Other 
factors,  such  as  fat  quality  is  more  important,  as  are  the  PH  levels  or  iodine 
levels.  Different  types  of  products  will  require  different  qualities  that  will  be 
prescribed  by the  processors in their orders  to the slaughterhouses.  This may 
then be articulated to particular farming practices. For example, a certain type 
of processing may require meat that has low unsaturated fatty acids, and that 
can then be obtained through particular ways of feeding the animals.  

(7) The boar taint smell comes from the  fat,  so there  is  the  possibility to address 
this by removing the back fat from the meat, for example. However, this is costly. 
It is not clear whether this is being done in commercial conditions in the EU. 

(8) An  example  was  also  given  of  how  vaccination  can  be  used  to  manage  fat 
content. Scheduling the vaccination at different times produces different qualities 
(more fat or less). For example, in Italy Improvac is used at 8 weeks to manage 
the amount of fat in the animal so that it fits the requirements for Parma ham 
production. To apply this approach in a manner that is suitable to each market, 
conversations are required between farmers and processors.  

Topic 5: Practices to raise consumer awareness and increase the market value 
of meat 

(1) The absence of active involvement from retailers and consumers in this domain 

was noted by several stakeholders.   

(2) Complaint management – there was an example provided from Germany of how 
complaints received by retailers in relation to boar taint are not passed further 
back down the supply chain. This was in line with the findings appearing in the 
report,  whereby  no  examples  were  provided  of  retailers  who  have  done  this 
differently/successfully.  

(3) Stakeholders  mentioned  that  it is  difficult to  add  value to  such  products  when 

consumers are not aware of these practices in the first place.  

(4) The  use  of  the  term  ‘consumer  acceptance’  was  found  to  be  problematic  as 
consumers have little knowledge or say in the issue, and the critical points are 
really consumer attitudes and behaviour.  

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Second Advisory Board meeting – 11 October 2018, Brussels 

Introduction and objectives 

These notes summarise the outcomes of the second Advisory Board meeting organised 
by DG SANTE and ICF for the Study on “Establishing best practices on the production, 
the processing and the marketing of meat from uncastrated or immunocastrated pigs”. 
Additional information on the meeting objectives and scope are detailed in the meeting 
presentation provided separately by ICF. The meeting was attended by 11 stakeholder 
representatives, DG SANTE and members of the ICF research team. 

Action points 

  All documents will be revised to ensure that the terms ‘boar taint’, ‘androstenone’ 
and ‘skatole’ are being used accurately and these should be properly explained 
in the text.   

  Additional  specific  edits  will  be  made  to  the  documents  based  on  feedback 

presented at the meeting.  

  Copies  of  the  additional  case  study  will  be  provided to the  stakeholders  if it  is 

approved.  

Next steps 

ICF will finalise the draft documents based on feedback and additional evidence received 
during the meeting and through the remaining follow-up research.  

Finalised versions of the best practice documents will be provided to all stakeholders.  

Summary of the meeting 

The meeting began with a round of introductions by the participants. ICF then presented 
a brief introduction to the study, meeting objectives and the current state of play.  

  The study is the first part of a two-part project. 
  This  part  of  the  project  is  meant  to  collect  into  a  single  document  a  basis  of 
knowledge  on  best  practices,  presented  in  the  form  of  a  “toolbox”  of  different 
options, explaining what the options are and their advantages and disadvantages. 
The document is to be  structured in  eight  sections  addressing eight  questions, 
and addressed at four distinct target audiences: (i) farmers, (ii) slaughterhouses, 
(iii) food processors, and (iv) retail and food services. 

  The second part of the study will build on the material collected in the first part, 
and will focus on disseminating the best practices in the form of communication 
material, and through events.67  

In the meeting the study team presented the main revisions done to each of the eight 
documents, based on the feedback received from the previous meeting.  

Cross-cutting comments  

(1) In the previous meeting,  concerns  were  voiced  on the  overall structure of the 
report.  Some  stakeholders  found  the  use  of  ‘advantages’,  ‘disadvantages’  and 
‘further reading’ to  be inadequate.  There  was  a  desire  for  both more  technical 
information  and  greater  use  of  examples.  ICF  used  this  feedback  to  make 
amendments  to  the  structure.  ‘Things  to  consider’  have  been  included 
throughout the report to highlight important practical considerations and ‘further 
reading’  has  been  amended  to  focus  only  on  practical  guidance  and  including 

67 The call for tender is available at: https://etendering.ted.europa.eu/cft/cft-

display.html;eTenderingPublic=ImHX7_9ZI9T9NUnwwtPx64OUTFRaclXcuwgviZgZWroGn3nqOy0L!-
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highlighted  examples  throughout  the  text.  The  changes  of  the  structure  have 
been received positively by  stakeholders. Additional editing would be welcome 
to  highlight  different  elements  and  introduce  additional  break  in  the  text. 
Additional  visuals  were  also  suggested  as  a  way  to  improve  readability.  There 
will  be  a  greater  opportunity  to  invest  in  additional  visuals  during  the 
dissemination phase of the project (phase 2).   

(2)  At  the  previous  meeting,  it  was  felt  that  the  format  used  did  not  provide 
appropriately  engaging  material  to  encourage  stakeholders  to  transition  away 
from  surgical  castration.  Stakeholders  felt  that  using  success  stories  and  a 
narrative approach would be helpful. The best practice documents are designed 
as a toolbox, which provides for limited opportunities to add examples. However, 
several  references  to  specific  experience  and  countries  have  been  added 
throughout.  Furthermore, ICF  has  written three  case  studies to  be  included  in 
the final report as an Annex. Copies of two such case studies were provided to 
attendees. One additional case study has been written but was pending approval 
from the interviewee at the time of the Advisory Board meeting. Examples of the 
use of immuno-castration in Spain may also be added to the documents, pending 
the reception of additional information from the relevant stakeholders.  

(3) Concerns were voiced that the order of the documents does not flow and that it 
would  be  better  to  group  information  by  entire  males  and  by  vaccinated  pigs 
rather  than  by  points  in  the  supply  chain.  ICF  clarified  that  the  order  and 
organisation of information was stipulated by the contract with DG SANTE. There 
may be opportunities to present the information in a different way during phase 
2. 

(4) Across the documents, stakeholders felt that the use of ‘skatole’, ‘androstenone’ 
and ‘boar taint’ should be clearer and more accurate. Information explaining to 
the reader what these two compounds are and the causes of boar taint should 
also be included in the documents.  

Below  is  a  summary  of  key  points  raised  in  the  discussion  on  each  of  the  topics 
presented.  

Q1. Farmers – uncastrated pigs: management techniques  

Feeding 

(1) Following concern about the evidence for chicory root being effective within 3-4 
days, the study team explained that this was on the basis of a scientific study. 
The study team clarified also that, although the literature is not included in the 
best practice documents, there is a more detailed section within the final report 
which describes each of the practices and is fully referenced.  

(2) For chicory root, silo management is a crucial issue and should be included as a 

‘thing to consider’. 

(3) For the cost information included, it would be helpful to not only have the overall 

cost of the food, but also how much feed options cost per pig.  

(4) The inclusion of grain-based or  low-protein diets alongside diets  with adjusted 
amino acids was felt to be potentially confusing and contradictory. This aspect 
needs  further  explanation  in  the  text,  to  highlight  to  the  reader  trade-offs 
between different feeding solutions. 

(5) Under commercial feed solutions, the text currently states that these impact both 
androstenone  and  skatole.  This is  an  error  and  should  be  amended  to  remove 
mention of an impact on androstenone.  

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(6) The  text  on  wet  feeding  currently  lists  lowered  manure  production  as  an 
advantage. This could be read as  implying  that if wet feeding is used, pigs do 
not need to  be  given  access to  additional sources  of  water.  This is  against EU 
regulations  and  not  a  best  practice.  The  text  should  clearly  mention  that 
continuous access to water should still be provided in wet feeding systems.  

(7) The point  was  made that,  when  considering  the  use of additives and different 
types of feed, it is also important that the feed tastes good, as this may otherwise 
have a negative impact on intake. This should be included as a ‘thing to consider’ 
in the documents.  

(8) Reducing competition at feeding is more an issue of housing and infrastructure 
than of feeding and should be considered alongside other housing issues. It may 
make  sense  to  reorganise  the  documents  to  better  reflect  the  order  in  which 
considerations should be made. ICF will follow up to confirm what order makes 
the most sense.  

Housing/flooring 

(1) When discussing sex separation and its advantages and disadvantages, the text 
presented  in  Q1  should  be  clearly  aligned  with  the  text  on  sex  separation 
presented in Q4.  

(2) Under  slatted  floors,  the  text  currently  states  that  slatted  floors  may  pose  a 
welfare  concern.  This  should  be  revised  to  state  that  ‘fully  slatted’  floors  may 
pose a welfare concern.  

(3) The question  was  raised of  whether the  use of edible  materials  as enrichment 
may have a negative influence on boar taint. There is no apparent research on 
this,  but  it  cannot  be  removed  as  this  is  a  legal  requirement.  As  most  edible 
enrichment is fibre, it is unlikely to have a negative effect but ICF will check to 
see if there is any research that suggests otherwise.  

Breeding 

(1) The section on breeding should be revised to clarify that the use of sperm from 

terminal sires only represents one half of the genetic material of pigs. 

Transport 

(1) There  were  several  concerns  regarding  the  inclusion  of  ‘transport’  as  a  best 
practice.  Although  one  study  has  been  published  which  found  a  link  between 
length  of  transport  and  androstenone68,  some  stakeholders  have  carried 
additional research on  very  large samples  and have  not  been  able to replicate 
these findings. ICF will therefore remove reference to this as a best practice but 
rather mention it as a ‘thing to consider’, while adding further information on this 
aspect in the main report. 

(2) Cleanliness during transport as well as the fasting period before slaughter were 
felt  to  have  a  clearer  impact  on  boar  taint.  The  section  will  be  revised  and 
shortened  to  highlight  cleanliness  and  the  use  of  a  fasting  period  before 
slaughter. Reference to transport as an important welfare consideration and links 
to existing transport guidance will remain in the text.  

68 Wesoly et al. (2015) Pre-slaughter conditions influence skatole and androstenone in adipose tissue of boars. 

Meat Science 99: 60-67. Available at:  https://www.sciencedirect.com/science/article/pii/S0309174014002800  

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Q2. Farmers – immunocastrated pigs: vaccination  

(1) There were some concerns around the terminology used for immunocastration, 
including the use of the term ‘vaccination’. However, no logical alternatives were 
suggested.  

(2) Some additional edits to the text have been provided by the representative from 
Zoetis.  It  was  also  mentioned that heavier  pigs  are  in  fact  easier  to vaccinate 
than smaller pigs as they are less agile and the text should be revised to reflect 
this.  

Q3.  Farmers  –  immunocastrated  pigs:  provide  assurance  to  slaughterhouses 
that  immunocastrated  pigs  do  not  present  detectable  boar  taint  and  Q5. 
Slaughterhouses – immunocastrated pigs: obtain assurance from farmers that 
immunocastrated pigs do not contain detectable boar taint 

(1) There was one question regarding the usefulness and the efficacy of checks at 
slaughterhouse level when checks are being performed at farm level. ICF clarified 
that the need to include both checks at farm level and at slaughterhouse level 
was a requirement for the project.  

(2) The text should better clarify the circumstances in which tests at slaughterhouse 

level take place, for example with farmers new to the process. 

(3) It  was  suggested  that the section on visual  checks  at the  farm  in  Q3 could  be 

better presented, e.g. as a box. 

(4) Reference in Q3 to checks conducted by Zoetis should be in the present tense, 

not the future tense. 

Q4.  Slaughterhouses  –  uncastrated  pigs:  detect  boar  taint,  quantify  and 
manage positive carcasses 

(1) ICF  clarified  that  the  current  information  present  on  price  per  carcass  for 
detection services will be replaced by information on price per hour, as this is 
how  the  relevant  service  is  priced  to  customers,  and  the  price  per  carcass  is 
dependent on the speed of the slaughter line.  

(2) The  text  currently indicates that  chemical  testing  is  not  yet  available  but new 
methods  are  under  development.    It  was  clarified  that  one  such  method  is 
expected to be implemented in a slaughterhouse within a year. Considering this, 
it  may  be  helpful  to  include  information  in  the  text  on  the  benefits  of  using  a 
chemical  or  instrumental  method,  including  how  it  can  be  connected  to  the 
penalty system and how it can be used to set quantitative industry standards. 
ICF  clarified  that  it  cannot  reference  any  method  in  development  as  the 
Commission’s brief is for only methods currently used in commercial conditions 
to be included. 

(3) The text currently presents the human nose method as delivering ‘robust results’ 
but does not  mention  the  risk  of false negatives. The text will be amended to 
communicate the uncertainty that remains, since the method is not fool-proof.  

(4) The  text  should  also  mention  providing  information  to  clients  on  detection 

procedures as a best practice.  

(5) The Danish Technological Institute should be added to the list of contractors that 

may assist with boar taint detection.  

(6) The practice of ‘Non-detection - slaughter of entire males at low weight’ should 
be revised to reflect that although low weight is used in the UK and Ireland, in 
Spain  and  Portugal,  pigs  are  raised  to  comparatively  heavier  weights  and 

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Final report 

masking is used as a solution to boar taint. The relevant text should therefore 
be “… through on-farm practices or by slaughtering animals at a lower weight or 
by masking techniques.” 

Q6. Food processors – uncastrated pigs: deal with meat with detectable boar 
taint 

(1) No  specific  comments  were  made  on  processing  and  dealing  with  meat  with 

detectable taint.  

Q7.  Retailers  and  food  services  –  uncastrated  pigs:  promoting  meat  from 
uncastrated pigs and Q8. Retailers and food services – immunocastrated pigs: 
promoting meat from immunocastrated pigs  

(1) The current text should further emphasise the practice of combining marketing 
material  that  highlights  the  animal  welfare  benefits  of  non-castration  with 
information  that  highlights  other  benefits,  such  as  environmental  or  human 
health aspects. Examples of this include Delhaize and Colruyt.  

(2) ‘Red tractor’ is described in the text as an animal welfare label, however it is a 
label  used  to  highlight  quality  and  Britishness.  The  text  should  be  revised  to 
reflect this.  

(3) The text on “Beter leven” should mention that non-castration applies not only to 

the “one star” label but also to the “two stars” label. 

(4) Consumers differ in their perceptions of boar taint, and these perceptions may 
differ  again  based  on  the  type  of  product  being  consumed.  This  should  be 
included in the text, as a ‘thing to consider’. A suggestion was also made that 
this could be represented graphically, identifying the spectrum of differences in 
consumer tastes and differences in the level of boar taint. This suggestion will 
be included in recommendations for the dissemination phase.  

Dissemination 

The advisory board then discussed in broad terms the next phase of the dissemination 
of the information to stakeholders. 

(1) Rather  than  focusing  dissemination  on  a  specific  point  in  the  supply  chain,  it 
would be helpful to host dissemination activities that bring together actors across 
a supply chain.  

(2) Engaging stakeholders in the topic was cited as a main issue with dissemination. 
For much of the pig industry in Europe, there is no sense of urgency on this topic 
and  in  countries  such  as  Romania  and  Poland,  moving  to  entire  males  or 
immunocastration is not considered to be feasible.  

(3) There has been a historic lack of  engagement with consumer  organisations  on 

this issue, and this was cited as a barrier to dissemination.  

(4) Retailers  are  also  difficult  to  engage  with  on  this  issue.  There  is  a  fear  for 

reputation loss.  

(5) Emphasising success stories would be an effective way of building interest in the 
topic – the best practices would then appeal to stakeholders who have first been 
convinced by success stories.  

(6) The  communication  strategy  would  be  usefully  structured  around  an 
understanding  of  the  various  bottlenecks  in  transitioning  to  entire  males, 

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Final report 

including the lack of urgency, incentives to maintain the status quo and the fact 
that risks and benefits are not allocated evenly along the chain.  

(7) Videos provide a good option for dissemination. Any materials produced should 

be in all EU languages. 

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Annex 7 References 

This annex lists the references reviewed for the data collection task. References are 
mapped against the study topics and countries they cover. 

Reference 

ALCASDE (2009). Study on the improved methods for 
animal-friendly production, in particular on alternatives 
to the castration of pigs and on alternatives to the 
dehorning of cattle. European Commission. Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/
aw_prac_farm_pigs_cast-alt_research_alcasade_final-
report.pdf  

Allen et al. (1997). Effect of nutrition and management 
on the incidence of boar taint. In: Boar taint in entire 
male pigs. Proceedings of a meeting of the EAAP working 
group "Production and Utilisation of Meat from Entire 
Male Pigs"; 1997 Okt 1-3; Stockholm, Sweden. 
Wageningen, the Netherlands: Wageningen Pers; 1997. 
p.88–91. 

Aluwé et al. (2009). Early and reliable detection of boar 
taint and genetic predisposition. Flanders Research 
Institute for Agriculture, Fisheries and Food. Available: 
https://pure.ilvo.be/portal/en/projects/vroegtijdige-en-
betrouwbare-detectie-van-berengeur-en-van-de-
genetische-aanleg-ervan(902ccf1a-403b-4087-ad4d-
085938e2f550).html  

Aluwé et al. (2011a). Influence of soiling on boar taint in 
boars. Meat Science, 87:3, pp. 175-179. Available: 
https://pure.ilvo.be/portal/en/publications/influence-of-
soiling-on-boar-taint-in-boars(c52065ec-c378-45d2-
a37f-52c10eaae493).html  

Aluwé et al. (2011b). Influence of breed and slaughter 
weight on boar taint prevalence in entire male pigs. 
Animal, 5:8, pp. 1283-1289. Available: 
https://www.cambridge.org/core/journals/animal/article
/influence-of-breed-and-slaughter-weight-on-boar-taint-
prevalence-in-entire-male-
pigs/139CA9B5D3C4A6D2477C0E3D5065DF8F  

Andersson et al. (1997). The effects of feeding system, 
lysine level and gilt contact on performance, skatole 
levels and economy of entire male pigs. Live Prod Sci, 
51:1-3, pp. 131–40.  

Backus et al. (2008). Removing the taint: Bottlenecks 
and possible directions for a solution in the marketing of 
the meat of non-castrated male pigs. Wageningen UR. 

Backus, G. Best practices by Dutch farms and supply 
chain companies. Unpublished.  

ToR 
issues 

Cross-
cutting 

Topic/prac
tice 

Country  

Cross-cutting 

EU 

1 

4 

1 

1 

1 

Cross-
cutting 

Cross-
cutting 
(entire 
males) 

Wet feeding 
(incl. feeding 
with whey) 

EU 

Boar taint 
detection 
methods 

BE 

Housing 

BE 

Breeding and 
selection at 
slaughter 

BE 

N/A 

Feeding - 
wet feeding 
(incl. feeding 
with whey) 

Cross-cutting 

NL 

Cross-cutting 
(entire 
males) 

NL 

Backus, G., Raedts, G., and van der Sanden, A. (2017). 
Praktisch en effectief oplossen en berengeur met inuline. 
Connecting agri&food. 

1 

Feeding 

NL 

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meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

Baltussen et al. (2008). Ban on castration of boars in the 
Netherlands: modelling economic consequences of 
options. Available: 
https://www.researchgate.net/publication/41090322_Ba
n_on_castration_of_boars_in_the_Netherlands_modeling
_economic_consequences_of_options  

Batorek et al. (2012). Meta-analysis of the effect of 
immunocastration on production performance, 
reproductive organs and boar taint compounds in pigs. 
Animal, 6:8, pp. 1330-1338. Available: 
https://www.cambridge.org/core/services/aop-
cambridge-core/content/view/S1751731112000146  

Cross-
cutting 

Cross-cutting 

NL 

2, 3 

Cross-
cutting 

EU 

Bekaert et al. (2013). Evaluation of different heating 
methods for the detection of boar taint by means of the 
human nose. Meat Science, 94:1, pp. 125-132. 
Available: 
https://www.sciencedirect.com/science/article/abs/pii/S
0309174013000296  

4 

Boar taint 
detection 
methods 

N/A 

Cross-
cutting 

Cross-cutting 

EU 

1 

Housing 

NL 

Cross-
cutting 

Cross-
cutting 

Cross-cutting 

EU 

Cross-cutting 

EU 

Berg et al. (2016). 'Pig castration: will the EU manage to 
ban pig castration by 2018?', Porcine Health 
Management, 2:29. Available: 
https://porcinehealthmanagement.biomedcentral.com/ar
ticles/10.1186/s40813-016-0046-x  

Binnendijk et al. (2013). Effect van licht, groepsgrootte 
en schuilwand op gedrag van beren. Wageningen UR 
Livestock Research. 

Boars heading for 2018. Available: 
http://boars2018.com/  

Bonneau et al. (2017). Potential sensitivity of pork 
production situations aiming at high-quality products to 
the use of entire male pigs as an alternative to surgical 
castrates. Animal 16:1-9. Available: 
https://www.cambridge.org/core/services/aop-
cambridge-
core/content/view/49AD5E79CDCC5B9C0A96118BA54D
10BF/S1751731117003044a.pdf/potential_sensitivity_of
_pork_production_situations_aiming_at_highquality_pro
ducts_to_the_use_of_entire_male_pigs_as_an_alternati
ve_to_surgical_castrates.pdf  

Boulet et al. (2017). Influence of TAINTSTOP, an 
innovative feed concept on boar taint. BAMST. Available: 
http://www.ca-
ipema.eu/download/289/documents/oieras/orals_oeiras/
2_N_3_Guy_Janssens.pdf  

Burgers, R. (2018). Vuile beren stinken harder, 
PigBusiness, Available: 
https://www.pigbusiness.nl/artikel/82507-vuile-beren-
stinken-harder/  

Byrne, D.V., Thamsborg, S.M. and Hansen, L.L. (2008). 
A sensory description of boar taint and the effects of 
crude and dried chicory roots (Cichorium intybus L.) and 

1 

1 

1 

Feeding 

EU 

Housing 

FR 

Feeding – 
Chircory root 

N/A 

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meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

inulin feeding in male and female pork. Meat Science, 
79(2), 252-269. 

Čandek-Potokar et al. (2010). Effect of 
immunocastration (Improvac©) in fattening pigs I: 
growth performance, reproductive organs and 
malodourous compounds. Slov Vet Res 47:2, pp. 57-64. 
Available: 
https://www.researchgate.net/publication/228882912_E
ffect_of_imunocastration_ImprovacR_in_fattening_pigs_
I_Growth_performance_reproductive_organs_and_malo
dorous_compounds  

Čandek-Potokar, M., Prevolnik, M., and Škrlep, M. 
(2014). ‘Testes Weight is not a reliable tool for 
discriminating immunocastrates from entire males’. 
Paper presented to International Symposium on Animal 
Science, Belgrade-Zemun, 23-25 September. Available: 
https://www.researchgate.net/publication/273767098_T
ESTES_WEIGHT_IS_NOT_A_RELIABLE_TOOL_FOR_DISC
RIMINATING_IMMUNOCASTRATES_FROM_ENTIRE_MALE
S   

Čandek-Potokar, M., Škrlep, M., and Zamaratskaia, G. 
(2017). Immunocastration as Alternative to Surgical 
Castration in Pigs, Theriogenology Rita Payan Carreira, 
IntechOpen, DOI: 10.5772/intechopen.68650. Available: 
https://www.intechopen.com/books/theriogenology/imm
unocastration-as-alternative-to-surgical-castration-in-
pigs  

Castrum consortium (2016). Pig castration: methods of 
anaesthesia and analgesia for all pigs and other 
alternatives for pigs used in traditional products. 
European Commission. Available: 
http://boars2018.com/wp-
content/uploads/2017/02/Castrum-study.pdf  

Civic Consulting (2013). Study and economic analysis of 
the costs and benefits of ending surgical castration. Part 
2 – Country studies. European Commission. Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/
aw_prac_farm_pigs_cast-alt_research_civic_pt2-
country-studies_20131202.pdf  

Claudi-Magnussen, C., Kristensen, L., and Tørngren, M. 
Use of tainted boar meat for processed meat products. 
Danish Meat Research Institute. Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/
aw_prac_farm_pigs_cast-alt_emp_use-of-tainted-boar-
meat.pdf  

1, 2 

Cross-cutting 

SI 

3, 5 

SI 

Physical 
signs of 
immunocastr
ation 

2, 3, 5, 8 

Immunocastr
ation – 
cross-cutting 

EU 

Cross-
cutting 

Cross-cutting 

EU 

Cross-
cutting 

Cross-cutting 

EU 

6 

Processing 

EU 

Colruyt Group (n.d.). Alternative for castration of pigs. 

7 

COST (2016). Innovative approaches in pork production 
with entire males. Available: 
http://www.cost.eu/COST_Actions/ca/CA15215  

Cross-
cutting 

Marketing of 
meat 

Belgium 

Cross-cutting 

EU 

Dahlmans et al. (2007). Sensorische beoordeling van 
spekmonsters op berengeur. CCL NUTRICONTROL. 

4 

Detection 

NL 

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meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

Danish Meat Research Institute (2011). Validation of 
“human nose” based method for boar taint detection. 
Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/
aw_prac_farm_pigs_cast-alt_research_dmri_human-
nose-method.pdf 

Danish Technological Institute. Sorting and optimized 
use of entire male pig meat. Available: 
https://www.dti.dk/specialists/sorting-and-optimized-
use-of-entire-male-pig-meat/34918  

De Campeneere et al. (2017). Farm specific strategies to 
reduce boartaint. Flanders Research Institute for 
Agriculture, Fisheries and Food. Available: 
https://pure.ilvo.be/portal/en/projects/bedrijfsspecifieke
-strategieen-voor-de-reductie-van-berengeur(6b2eb708-
aa94-4c72-b248-4b3ae4da779e).html  

De Kimpe, K. Les alternatives à la castration chirugicale 
des porcelets: immunocastration par l’improvac. 
Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/
aw_prac_farm_pigs_cast-alt_vaccination_pres_de-
kimpe_20110325.pdf  

Deen et al. An economic model to assess costs and 
benefits of Improvac to the swine producer for control of 
boar taint. In the 20th International Pig Veterinary 
Society Congress, 22-26 June 2008. 

DLO (2014). CAMPIG: Consumer acceptance in the 
European Union and in third countries of pig meat 
obtained from male pigs not surgically castrated. 
European Commission. Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/
aw_prac_farm_pigs_cast-
alt_research_campig_20140706.pdf  

4 

6 

1 

2 

2 

7 

Dunshea, F. R, et al. (2013) The effect of immunization 
against GnRF on nutrient requirements of male pigs. 

2, 3 

7 

1 

Dutch Better Life Label (unpublished). Berengeur 
detectieregels uit de Beter Leven criteria voor 
varkensslachthuizen welke per 1-1-18 van kracht 
worden. 

European Commission (2017) Tail docking. Available: 
https://ec.europa.eu/food/animals/welfare/practice/farm
/pigs/tail-docking_en  

European Commission. Alternatives to pig castration: 
European Declaration on alternatives to surgical 
castration of pigs. Available: 
https://ec.europa.eu/food/animals/welfare/practice/farm
/pigs/castration_alternatives_en  

European Federation of Animal Science. Entire male pigs 
and immunocastration as alternatives to surgical 
castration of male piglets: opportunities and drawbacks 
(part 1) (with COST Action IPEMA). 69th Annual Meeting 
of the European Federation of Animal Science. 

168 

Detection – 
hot water 
method 

DK 

Processing 

DK 

Cross-cutting 

BE 

Immunocastr
ation 

EU 

Costs and 
benefits of 
vaccination 

N/A 

Consumer 
acceptance 

EU 

Nutrition of 
vaccinated 
pigs 

N/A 

Cross-cutting 

NL 

Cross-cutting 

EU 

N/A 

N/A 

EU 

Cross-
cutting 

Cross-cutting 

EU 

 
 
 
 
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meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

European Food Safety Agency (2004). Opinion of the 
Scientific Panel on Animal Health and Welfare (AHAW) 
on a request from the Commission related to welfare 
aspects of the castration of piglets. EFSA Journal, 2:7, 
pp. 1-18. Available: 
https://www.efsa.europa.eu/en/efsajournal/pub/91  

European Medicines Agency. Improvac. Annex I. 
Summary of product characteristics. Available: 
http://www.ema.europa.eu/docs/en_GB/document_libra
ry/EPAR_-
_Product_Information/veterinary/000136/WC500064060
.pdf    

Font-i-Furnols (2012). Consumer studies on sensory 
acceptability of boar taint: A review. Meat Science 
92(4): pp. 319-329. Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/
aw_prac_farm_pigs_cast-alt_detection_2012_consumer-
studies_sensory-acceptability.pdf  

Font-i-Furnols et al. (2012). Effect of variation against 
gonadotrophin-releasing factor on growth performance, 
carcass, meat and fat quality of male Duroc pigs for dry-
cured ham production. Meat Science, 91, pp. 148-154. 
Availabe: 
https://www.sciencedirect.com/science/article/abs/pii/S
0309174012000095  

Font-i-Furnols et al. (2016). Evolution of testes 
characteristics in entire and immunocastrated male pigs 
from 30 to 120 kg live weight as assessed by computed 
tomography with perspective on boar taint. Meat 
Science, 116: pp. 8-15. Available: 
https://www.sciencedirect.com/science/article/abs/pii/S
0309174016300092  

Fredriksen, B., Sibeko Johnsen, A.M., and Skuterud, E. 
(2011). Consumer attitudes towards castration of piglets 
and alternatives to surgical castration. Res. Vet. Sci. 
90(2): pp. 352-357. Available: 
https://www.sciencedirect.com/science/article/pii/S0034
528810002250  

Gispert et al. (2010). Carcass and meat quality 
characteristics of immunocastrated male, surgically 
castrated male, entire male and female pigs. Meat Sci. 
85(4): pp. 664-70. Available: 
https://www.sciencedirect.com/science/article/abs/pii/S
0309174010000938  

Guarini, C., Minelli, G., Pinna, A., Schivazappa, C., 
Ventura, G., and Virgili, R. Effect of immunocastration on 
some key technological and sensory quality parameters 
of Italian typical dry-cured ham. SSICA, Vet 
Practitioners, and Zoetis, at Congreso mundial del 
jamón/World congress of dry-cured hams, 28-30 May 
2013. 

Hansen, L., Larsen, A., Jensen, B., Hansen-Møller, J., 
and Barton-Gade, P. (1994) Influence of stocking rate 
and faeces deposition in the pen at different 

169 

1, 2 

Cross-cutting 

EU 

1 

Cross-cutting 

EU 

7 

Consumer 
acceptance 

EU 

3, 5 

Spain 

Effects of 
vaccination 
on quality of 
meat 

1, 2, 3, 4, 
5 

Physical 
characteristic 

N/A 

7, 8 

Consumer 
attitudes 

N/A 

6 

Processing 

N/A 

2, 3 

Cross-cutting 

IT 

1 

Housing 

N/A 

 
 
 
 
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Final report 

temperatures on skatole concentration (boar taint) in 
subcutaneous fat. Animal Science, 59(1), 99-110. 

Hansen, L., Mejer, H., Thamsborg, S., Byrne, D., 
Roepstorff, A., Karlsson, A., and Tuomola, M. (2006). 
Influence of chicory roots (Cichorium intybus L) on boar 
taint in entire male and female pigs. Animal Science, 
82(3), 359-368. 

Haugen, J. Detection of Boar Taint: need for harmonised 
methods and rapid methods. Available: 
https://pdfs.semanticscholar.org/ee1/52141525231ddb5
e595bb921db20537eefaf.pdf  

Improvac (n.d.). Environmental product declaration for 
IMPROVAC. 

1 

4 

8 

Feeding – 
Chicory root 

N/A 

Detection 

NO 

Cross-cutting 

N/A 

Improvac and Zoetis. Testosteron test. 

2, 3 

Cross-cutting 

IT 

Improvac. User Safety and Devices, Improvac Managed 
Males.  

Institute of Agriculture and Food Research and 
Technology (2015). Study on how to achieve reduction 
of boar taint compounds by breeding, feeding and 
management techniques. European Commission. 
Available: 
https://ec.europa.eu/food/sites/food/files/animals/docs/
aw_prac_farm_pigs_cast-
alt_research_irta_20150216.pdf  

Janssens, G., Boulet, R., Reuter, W., and Hardy, N. 
(2018) TAINTSTOP, an innovative feed concept: 
Influence on Boar Taint. Available: http://www.ca-
ipema.eu/download/289/documents/oieras/orals_oeiras/
2_N_3_Guy_Janssens.pdf 

Jensen et al. (1997). Effect of various carbohydrate 
sources on the production of skatole in the hind gut of 
pigs and skatole concentration in blood plasma. In: Boar 
taint in entire male pigs. Proceedings of a meeting of the 
EAAP working group "Production and Utilisation of Meat 
from Entire Male Pigs"; 1997a Okt 1-3; Stockholm, 
Sweden. Wageningen, the Netherlands: Wageningen 
Pers; 1997. p.80-3. 

Jensen, B. B. (2006). Prevention of boar taint in pig 
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Kirk, G. (2016). ‘Improvac could be Europe’s high-
welfare castration solution’, PigWorld, 01 April. 
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world.co.uk/news/welfare/improvac-could-be-europes-
high-welfare-castration-solution.html  

Kiss et al. (2017). ‘Ceva Valora® as an Efficient 
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Kjeldsen, N. (1993). Practical experience with production 
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170 

2 

1 

1 

1 

1 

2 

2 

1 

Immunocastr
ation 

N/A 

Cross-cutting 

EU 

Feeding – 
Taintstop 

EU 

N/A 

Feeding - 
sugar beet 
(non-starch 
polysaccharid
es-dietary 
fibre) 

Cross cutting 

N/A 

Immunocastr
ation 

UK 

Immunocastr
ation 

N/A 

Feeding - 
fasting prior 

DK 

 
 
 
 
Establishing best practices on the production, the processing and the marketing of 
meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

Denmark, 1992, (ed. Bonneau, M.), Institut National de 
la Recherche Agronomique, les colloques no. 60, pp. 
137–144 

Lagerkvist, C.J., Carlsson, F., and Viske, D. (2006). 
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biotech: A choice experiment. AgBioForum. 9:1, pp. 51-
58. Available: 
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lagerkvist.pdf  

7, 8 

SE 

(12-24 h) to 
slaughter 

Consumer 
acceptance 
of 
immunocastr
ation and 
production of 
entire males 

Le Rouzic (2016). ‘The AROME project: developing a real 
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partners/All-the-news/Project-AROME  

Lundström, K., Malmfors, B., Stern, S., Rydhmer, L., 
Eliasson-Selling, L., Mortensen, A. B., and Mortensen, H. 
P. (1994). Skatole levels in pigs selected for high lean 
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Mancini, C. M., Menozzi, D., and Arfini, F. (2017). 
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Mancini, C. M., Menozzi, D., Arfini, F., and Veneziani, M. 
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Martinez et al. (2016). Evaluation of different strategies 
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0309174016300080  

Mathur et al. (2012). A human nose scoring system for 
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0309174012000708  

Mons, G. (2018). Berenmesters Antonissen: 'Professie 
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berenmesters-antonissen-professie-zit-in-de-
stal/?tid=TIDP100319X153A73CA384A4E70BDA83C485E
5403C3YI5&utm_campaign=2018_PigBusiness&utm_me
dium=Email&utm_source=E-
mail&utm_content=201800805_PB_NB  

Morales et al. (2013). Growth performance and carcass 
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171 

1 

Breeding 

FR 

1 

8 

8 

6 

4 

1 

Breeding 

N/A 

Cross-cutting 

IT 

Cross-cutting 

IT 

Processing 

N/A 

Detection – 
human nose 

N/A 

DE and NL 

Feeding – 
taintstop 
feed 

Flooring and 
housing – 
enrichment 
practices; 
wean to 
finish 
grouping 

1 

Breeding 

N/A 

 
 
 
 
Establishing best practices on the production, the processing and the marketing of 
meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

https://academic.oup.com/jas/article-
abstract/91/8/3955/4731465?redirectedFrom=fulltext  

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Available: 
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ack/pdf/10.1186/s40813-017-0066-1  

Entire 
males – 
cross-
cutting 

Cross-cutting 

N/A 

7, 8 

Cross-cutting 

Germany 

4 

Detection 

EU 

1 

2 

7 

Feeding – 
protein 

EU 

Immunocastr
ation 

ES 

EU 

Consumer 
acceptance 
of tainted 
meat 

2, 3 

Cross-cutting 

IT 

2, 3, 5 

Immunocastr
ation 

IT 

2, 3 

Cross-cutting 

IT 

2, 3 

Cross-cutting 

Sweden 

Mörlein, D., and Schübeler, A.S. So gelingt der Dialog 
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Panella-Riera et al. (2016). Consumers' segmentation 
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0309174015301558  

Parolari, G. Dry-cured ham from immunocastrated pigs. 
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meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

Schübeler, A.S., and Mörlein, D. Wie reagieren 
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7, 8 

Cross-cutting 

Germany 

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Cross-
cutting 

Cross-cutting 

N/A 

ter Beek, V. (2018). ‘Rye: Influence on Salmonella and 
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Unknown (2014). ‘New project to measure boar taint on 
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Unknown (2016). ‘Biennial Report 2015-2016’, The Pig 
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Unknown (2016). ‘NPA briefing note on castration’, 
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Unknown (2017). ‘Norway: Close Cooperation in Pig 
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173 

1 

Feeding 

N/A 

7 

Marketing 

UK 

1, 2 

Cross-cutting 

BE 

Cross-
cutting 

Cross-cutting 

N/A 

4 

1 

Detection 

UK 

Feeding 

DK 

Cross-
cutting 

Cross-cutting 

UK 

1 

Cross-cutting 

UK 

Cross-
cutting 

Cross-cutting 

NO 

 
 
 
 
Establishing best practices on the production, the processing and the marketing of 
meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

Unknown (2017). ‘Pigs 2022 – Battling taint to protect 
our market’, PigWorld, 10 July. Available: 
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Cross-
cutting 

1 

1 

1 

8 

Unknown (2017). ‘Topigs: Less boar taint with the Nador 
concept’. Pig Progress, 30 Jan. Available: 
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PP008280W/  

Unknown (2017). 'Vitelia-voer dringt berengeur terug', 
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van Dooren, K. (2017). ‘The right terminal sire can 
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Vanhonacker, F. and Verbeke, W. (2011). Consumer 
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Wäckers et al. (2011). Boar taint detection using 
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Cross-cutting 

UK 

Breeding 

EU 

Feeding 

NL 

Breeding 

EU 

FR, NL, DE, 
BE 

Consumer 
acceptance 
of 
immunocastr
ation 

4 

Detection 

N/A 

Wageningen UR (2013). Boars on the way: results of the 
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Entire 
males – 
cross-
cutting 

Cross-cutting 

The 
Netherland
s 

Wouda, T. (2017). 'Vitelia vervolgt onderzoek 
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https://www.nieuweoogst.nu/nieuws/2017/04/29/vitelia
-vervolgt-onderzoek-beergedrag  

Xue et al. (1996). Breed differences in boar taint: 
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eed_Differences_in_Boar_Taint_Relationship_between_T
issue_Levels_of_Boar_Taint_Compounds_and_Sensory_
Analysis_of_Taint  

1 

1 

Zamaratskaia, G., and Krøyer Rasmussen, M. (2015). 
Immunocastration of male pigs – situation today. 
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https://www.sciencedirect.com/science/article/pii/S2211
601X15001546  

2, 3 

Feeding 

NL 

Breeding 

N/A 

Internation
al 

Age at 
immunocastr
ation; checks 
to ensure 
absence of 
boar taint 

174 

 
 
 
 
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meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

Zammerini, D., Wood, J. D., Whittington, F. M., Nute, G. 
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Zeng et al. (2002). Effects of active immunization 
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ects_of_active_immunization_against_GnRH_on_serum_
LH_inhibin_A_sexual_development_and_growth_rate_in
_Chinese_female_pigs  

1 

2 

Zoetis (n.d.) Implementation on-farm. Training program 
for the implementation of Improvac – Vaccine for the 
control of boar taint (unpublished) 

2 

Feeding – 
Chicory root 

N/A 

Immunocastr
ation 

N/A 

ES 

Supply chain 
assurance – 
control 
documents 

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from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – Final 
report 

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meat from uncastrated pigs or pigs vaccinated against boar taint (immunocastrated) – 
Final report 

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