Cutting the need for tail-docking : thermal comfort, air quality and light : why are my pigs tail-biting?
Date: 2017-01-31
Institutions: Directorate-General for Health and Food Safety
Subjects: animal welfare, livestock farming, swine

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CUTTING THE NEED FOR TAIL-DOCKING
THERMAL COMFORT, 
AIR QUALITY AND LIGHT
Why are my pigs tail-biting?

Pigs struggle to regulate their body temperature

Potential indicators of poor thermal comfort/air quality/lighting 
conditions, which could lead to tail-biting  

 ■ Lack of cleanliness
 ■ Restlessness/aggression
 ■ Huddling
 ■ Shivering
 ■ Playing with water and manure
 ■ Reduced appetite

 ■ Pigs laying on their sides and/or  

far apart

 ■ Excretion in the rest area
 ■ Panting, sneezing or coughing
 ■ Conjunctivitis.

What? Maintaining the right temperature and good air quality are extremely important in 
keeping  stress  levels  low.  Different  temperatures  zones  are  an  even  better  option.  In  cold 
climates, insulation, good bedding or a heating system can ensure thermal comfort. During 
warm weather, options include ground heat exchangers, air conditioning, floor cooling, misting 
systems, showers and wallows. Ventilation must limit the flow of cold air over sleeping areas 
and keep dust and ammonia levels to a minimum. It is also important for pigs to be able to 
avoid direct sunlight. Pigs must be kept in light with an intensity of 40 lux for a minimum 
period of 8 hours a day. As continuous lighting causes stress, a day and night rhythm should 
be maintained. Very bright lights should be avoided.

Why? Pigs have a very limited capacity to regulate their body temperature, and therefore 
need a stable environment that is close to their optimum temperature at all times, and which 
limits  non-seasonal  fluctuations.  Different  temperature  zones  that  cater  for  different  pigs’ 
needs  work  even  better.  If  pigs  are  denied  this,  they  become  listless  or  restless  and  may 
begin tail-biting.

Health and
Food Safety

Optimising  these  key  factors 
should  reduce  tail-biting  and 
remove the need for tail-docking.

1. ENRICHMENT 
MATERIAL

Pigs  have  a  strong  need  to  explore 
their  environment  and  to  search  for 
food  (sniffing,  biting  and  chewing).  If 
they  cannot  do  this,  they  get  bored 
and frustrated.

2. THERMAL COMFORT,  

AIR QUALITY  
AND LIGHT

Pigs  need  a  stable  environment  that 
is close to their optimum temperature 
levels,  draught-free 
and  humidity 
and  with  suitable  lighting  conditions.  
If  pigs  are  not  comfortable,  they 
become  frustrated  and  may  begin 
tail-biting.

3. HEALTH AND FITNESS
Good overall health is one of the best 
ways to avoid tail-biting. A pig in poor 
health is a stressed pig.

4. COMPETITION 
Pigs  prefer  to  forage,  eat  and  rest 
simultaneously. There should be enough 
space  and  resources  for  the  pigs  to 
meet  this  behavioural  need  and  thus 
avoid competition.

5. DIET
Pigs  need 
feed  of  adequate 
consistency,  as  well  as  the  right 
levels of minerals, fibre and essential 
amino  acids;  they  also  need  a 
sufficient  quantity  of  fresh,  good- 
quality water.

6. PEN STRUCTURE/ 
CLEANLINESS

Pigs  prefer  to  keep  different  areas 
of  the  pen  for  different  behaviours 
(resting,  feeding,  defecation).  A  dirty 
environment, especially in the feeding 
and resting area, is therefore a sign that 
something is wrong. It also, in turn, re- 
duces comfort and stresses the pigs.

How?  Various  heating,  cooling  and 
ventilation  options  are  on  the  market. 
For  direct  sunlight,  the  solution  could  be 
as  simple  as  fitting  blinds  on  windows. 
Keeping  pigs  in  semi-darkness  to  avoid 
attacks 
ineffective  and  should  be 
avoided.

is 

How do I know if I’m doing it right? 
Various  indicators  have  been  proposed, 
such  as  ensuring  temperature  variation 
does  not  exceed  4° C  over  24  hours, 
keeping  draughts  below  0.2  metres  per 
second  and  monitoring  CO2,  NH3  and 
humidity levels.

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How  much  does  it  cost?  Costs  vary 
according  to  country  and  the  options 
selected. 

Are  there  any  disadvantages? 
Not  all  ventilation  and  flooring  system 
combinations  are  as  effective  as  others. 
Experience  from  farmers  in  countries 
rearing  pigs  with  intact  tails  shows  that 
the  best  results  have  been  achieved  by 
incremental  modifications  to  ventilation, 
heating  and  pig  pen  designs  based  upon 
trial and error.

Temperature control at Timo Heikkilä’s farm, Finland

Did you know?

Some  farms  in  the  Nordic  region  are  using  the  latent 
heat  in  slurry  systems  to  heat  the  farm.  This  has  the 
added  benefit  of  cooling  the  slurry  and  reducing  the 
production of ammonia.

Jan Vugts
Senior Advisor, HKScan, Finland

‘What  is  most  important  is  that  the  design  of  the  pen, 
floor and climate system form an integrated system.’ 

Anne-Claire Berentsen
Scientific  employee  at  the  Animal  Welfare  Service 
of  the  Lower  Saxony  State  Office  of  Consumer  
Protection and Food Safety, Germany

‘Especially  for  weaners,  heated  flooring  in  the  lying 
(resting)  area  is  not  that  expensive  and  has  huge 
benefits  because  it  allows  for  a  warm,  comfortable 
lying  area  and  a  cooler  activity  area.  Therefore  the 
temperature in the overall compartment can be lower, 
which generally means better ventilation and a lower 
level of less noxious gas. It also gives pigs the option 
to choose between two temperature zones.’

Print 

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ISBN 978-92-79-67541-6
doi: 10.2875/692448
EW-01-17-289-EN-C

ISBN 978-92-79-67536-2
doi: 10.2875/67718
EW-01-17-289-EN-N