On-farm killing of pigs
EURCAW-Pigs Regional meeting East
17 November 2020
Inga Wilk

©FLI

©FLI

Main topics according to the discussions on day 1
I. Methods for the stunning and killing of non-viable pigs and piglets on farm
 Information about technical equipment

 With special consideration to one-step killing methods (without debleeding)

II. Methods for the mass depopulation of pigs in case of a disease outbreak (e.g.
African Swine Fever) gas killing methods: type of containers, technical parameters like gas concentration and exposure time,
animal categories

III. Process control and safeguarding animal welfare Key parameters according to the Council Regulation No. 1099/2009
 Animal-based measures for the state of consciousness and deathMethods for on-farm stunning and killing of pigs (overview)
Physical methods

Mechanicalmethods

Inhaled methods

Noninhaled
methods

 Penetrative
captive bolt

 Gas mixtures

Lethal injection

 Non-penetrating
captive bolt

 Gas-filled foam Percussive blow
to the head

Electricalmethods

Chemical methods

Electrocution forkilling pigs during
disease outbreak Firearm with freeprojectile
Individual stunning/killing, e.g. of non-viable
pigs at farm level(Its use is reserved toveterinarians!)

Stunning/killing ingroups  use formass depopulation ofpigs during disease
outbreaks
Knowledge and skills of the operator are crucial for a successful
performance of the methods with regard to animal welfare.

Mechanical methods(EFSA, 2020a; Lambooij and Algers, 2016; EFSA, 2004)

Penetrating methods

Non-penetrating methods

Penetrative captive bolt

Non-penetrating captive bolt (controlled
blunt force trauma)

Firearm with free projectile

Percussive blow to the head (manual
blunt force trauma)

Operating principle
 Brain concussion (with coup-contre-coup-effect) Brain haemorrhages
 Immediate unconsciousness

 Penetrating mechanical methods: prolonged unconsciousness due to Structural damage of brain tissue with haemorrhages
 Pressure waves within the fluid medium of the brain

Penetrative captive bolt
For pigs cartridge-driven captive bolt guns are used (EFSA, 2020a, 2004).

Difficult application on pigs (EFSA, 2020a, 2004):

1. small target area
2. deep position of the brain in the head with a mass of sinuses lying
between the frontal bone and the brain cavity

3. different skull shapes according to breeds

Penetrative captive bolt (EFSA, 2020a; LWK Nds. et al., 2018; LAVES, 2015; EFSA,2004; HSA, 2013)
Shooting position: perpendicular to the parietal bones, in the midline of theforehead, 1-2 cm above eye level, with the muzzle placed against the headand directed towards the tailDepending on different head shapes:

 Wedge-shaped head: 1 cm above eye level (as described above), with 25°
angulation of the device (tilting it slightly down)

 Steep head: 2-3 cm above eye level, with a right-angled base of the device
Sows, boars: ridge of bones 3-4 cm above the eyes with the muzzle placedslightly to the side of the midline aiming at the centre of the head use of another method recommended esp. for boars with clearly
pronounced sinuses and thus a very deep position of the brain in the skull

Penetrative captive bolt (Meier, 2020; Woods, 2012)
Two-step method  subsequent killing method is necessary
Recent studies on the use of different bolt guns on animals of different
weight classes as a single-step euthanasia method: Woods (2012): „Cash Dispatch Kit“ (Accles & Shelvoke, UK)  pigs up to
200 kg

 Meier (2020): two partly modified captive bolt guns, „Ferkelblitz“ forpiglets up to 5 kg and „Blitz-Kerner“ for piglets > 5 kg (Turbocut Jopp
GmbH, Germany)  pigs up to 30 kg

According to the law, after the captive bolt shot, even with these devices, akilling procedure must still follow in principle and until now.

Penetrative captive bolt (EFSA, 2020a; LAVES, 2015)
Further requirements:
Good restraint of the animal (minimise head movements, ensure adequate
shooting position and direction)

Suitable device (bolt length and diameter) and cartridge (bolt velocity)depending on animal category and age
Dry storage of cartridges
Daily inspection and cleaning of the device before and after its use (removal ofcontaminations and rust; sharpness of the bolt, retraction system)

Maintenance of the device by the manufacturer at least every two years

Penetrative captive bolt
Key parameters according to Council Regulation No. 1099/2009:• Position and direction of the shot
• Appropriate velocity, exit length and diameter of bolt according toanimal size and species (adequate captive bolt parameters)• Maximum stun to stick/kill interval(s)Firearm with free projectile (EFSA, 2020a; HSA, 2016)
One-step killing method

Minimal or no restraint of the animal; used to kill pigs from a distanceshooting at close range with handguns (from a distance below 10 cm) andshotguns (from a distance between 5 and 25 cm)

Shooting position: the same as for captive bolt
Sufficient kinetic energy of the projectile is necessary (penetration depth,
sufficient damage to the brain, brain concussion, instantaneous death)

Ideal ammunition: bullets constructed to fragment and/or deform within the skull
Work safety: ricochet of free bullets (when use in enclosed spaces,
surfaces)hardFirearm with free projectile
Key parameters according to Council Regulation No. 1099/2009:• Position of the shot

• Power and caliber of the cartridge• Type of projectileNon-penetrating captive bolt (EFSA, 2020a; Grist et al., 2018a, 2018b, 2017)
Cartridge-driven or pneumatic non-penetrating captive bolt guns (N-PCBG)

Zephyr EXL

Create controlled blunt force trauma

Recent studies support the use of N-PCBG as single-step killing method forneonatal piglets:
Grist et al. (2017, 2018a)-Zephyr EXL (Bock Industries): Kinetic energy of
27.7 J (120 psi), piglets up to 10.9 kg, restraint of the piglets`head on ahard surface is decisive

Grist et al. (2018b) – CASH Small Animal Tool (Accles & Shelvoke, UK):kinetic energy 47 J (brown 1-grain cartridge), restraint in a hammock,piglets up to 5 kg
CASH Small Animal Tool

Non-penetrating captive bolt
Key parameters:• Position and direction of the shot• appropriate velocity, diameter and shape of bolt according to animal size andspecies (captive bolt parameters)• Strength of the cartridge used or applied air pressure (in psi)
According to the Council Regulation No. 1099/2009, until now, the application of
non-penetrating captive bolt guns is not allowed for pigs!

Percussive blow to the head (EFSA, 2020a; LWK Nds. et al., 2018; Woods and Shearer, 2015,
TVT, 2014)

Two-step method  subsequent killing method is necessary
Acceptable for piglets up to 5 kg
Manually applied blunt force trauma, by hitting the head once with a ballpeen hammer, steel rod, wooden club or pipe with sufficient strength andprecision

Location: at the highest point between the eyes and the base of the ears
The object needs to be brought to the animal`s head, not the animal to theobject; no application over the edge of the pen wall !!

Zephyr EXL

Percussive blow to the head
Key parameter according to the Council Regulation No. 1099/2009:• Force and location of the blow
Low reproducibility, questionable reliability and effectiveness replacement by other methods is recommended

Zephyr EXL

Electrical killing methods (EFSA, 2020a; AVMA, 2020; LWK Nds. et al., 2018; Woods & Shearer, 2015,
EFSA, 2004)

Two kinds of electrical killing methods:
1. two-step method with head-only electrical stunning followed by ventricularfibrillation

2. one step-euthanasia method of head-to-body-application
Effect: grand mal seizure (unconsciousness), followed by ventricular fibrillation(cardiac arrest  death)

Zephyr EXL

Electrical killing: two step-method (EFSA, 2020a; TVT, 2018, LWK Nds. et al., 2018; EFSA,
2004)

First current cycle (head-only stunning):

Electrodes  head:between eyes and base of ears; application frombehind, at least 1.3 A for 4 s (heavy pigs: 1.8 A)
Prevention of pre-stun electrical shocks

 Adequate restraint of the animal; maintaining electrical contact
during collapse of the animal by the operator
Second current cycle (heart):

Currents with frequencies of 50 Hz for at least 8 s; electrodes: fromhead to sternum or from back to the chest or left and right of the ribs
directly behind the shoulder blade

Zephyr EXL

Electrical killing: one step-method (EFSA, 2020a; Lambooy and van Voorst, 1986)
Head-to-body-electrodes (spanning the head and heart at the sametime)
Injection of sedative drugs (e.g. azaperone) for agitated pigs, if
necessary
Adequate restraint for right placement of electrodes for sufficientduration of current application until deathLambooij and van Voorst (1986): mobile electrocution unit for mass
depopulation of swine (MPS/Marel) older than 1 week Conveyor belt as negative electrode, three chain curtains as
positive electrodes

Zephyr EXL

Electrical killing: electrocution of piglets up to 2 kg
Husheer (2017):

skin penetrating needle electrodes (size of 1 x 2 cm²) combined withelectrode gel
Application of a current of 0.75 A at a frequency of 400 Hz firstlaterolateral through the thorax for 5 s and after a break of 20-30 s
dorsoventral through the thorax for 5 s

Zephyr EXL

Electrical killing methods
Key parameter according to the Council Regulation No. 1099/2009:• Stunning parameters (minimum current, voltage, frequency, time to
exposure)• Frequency of calibration of the equipment• Optimisation of the current flow
• Prevention of electrical shocks before stunning• Position and contact surface area of electrodes

Zephyr EXLInhalant methods: CO2 (EFSA, 2020a; Woods and Shearer, 2015; Troeger, 2008; EFSA, 2004; Raj &Gregory, 1995; Gregory et al., 1990; Nattie, 1999; Cantieni, 1977; Eisele et al., 1967; Woodbury and Karler, 1960)

On farm level: precharged systems for piglets

Zephyr EXL

80 %, preferably 90 % CO2 for at least 10 minutes
One-step method

Advantages: stun/kill in groups, minimum amount of restraint and handling
Disadvantage: effect of CO2 and delayed onset of unconsiousness

1. Painful mucosal irritation in upper airways

2. Respiratory distress: stimulation of the chemosensible respiratory centre, increased
respiration rate (hyperventilation)  conscious perception as breathlessness within
the first 10-20 s

Inhalant methods: CO2 for mass depopulation of pigs (Gerritzen et al., 2012;
EFSA, 2004; EFSA, 2020a,b)Containerised gassing systems

 90 % CO2 in air (3 min)
 Argon, nitrogen and mixtures, 2 % residual oxygen (7 min) 30 % CO2 in argon or nitrogen (7 min)

Zephyr EXLInhalant methods: CO2
Key parameter according to the Council Regulation No. 1099/2009:• Carbon dioxide concentration• Duration of exposure• Quality and temperature of the gas

Zephyr EXLInhalant methods: high expansion gas-filled foam (EFSA, 2020a; Wallenbeck
et al., 2020; Balzer, 2017)high expansion foam filled with nitrogenPrinciple: foam burst upon contact with the animal and surrounding
materials, released gas results in stunning/killing of the animal

 Balzer (2017): first application on moribund suckling piglets in an open
system showed no advantages to CO2, latency period until last
movement 296.8±155.33 s, no rapid onset of death Wallenbeck et al. (2020): use of foam in closed system with modificationof foam supply and foaming agent on heavier pigs (27.8 ± 3.4 kg);
increased escape attempts with increasing foam level (avoidance
behaviour), loss of posture at 57.9 s, end of convulsions after 131.2 s;animals were unconscious or dead within 5 min after start of foam
production

Zephyr EXLInhalant methods: gas-filled foam
Further research on the emergency killing of piglets with investigations on the assured
Zephyr EXL
killing effect of the process
Possible key parameters:
 Bubble size (to prevent trachea displacement) Residual oxygen Expansion rate Sufficient foam production rate

 Gas source and gas purity
 Foam concentration
 Gas and water temperatureAnimal-based measures for the state of consciousness and death(EFSA, 2020a; Holmes et al., 2020; EFSA, 2013)

Animal-based measures (ABM) are measurable and objective outcome-based criteria
Zephyr EXL
to evaluate welfare.
Important welfare consequences in the on-farm killing process corresponding to thestate of consciousness: pain and fear

Pigs might experience pain and fear during ineffective killinga) With persistence of consciousness (stun failure) and/orb) During recovery of consciousness before death (re-awakening of theanimals).

ABM related to the state of consciousness after application ofphysical methods (EFSA, 2020a; EFSA, 2013)
ABM : state of consciousness(pain and fear as welfare
consequences)

Outcome in effectively stunned animals(low risk of pain and fear)

Outcome in ineffectively stunned or
re-awakening animals (high Zephyrrisk of EXL
pain and fear)

PostureLoss of posture, immediate collapse

Fail to collapse, attemptions to regain
posture after collapse

BreathingAbsence of (rhythmic) breathing, apnoea

Rhythmic breathing

Tonic/clonic seizures

Onset of tonic-clonic seizures soon after collapse

Fail to show tonic/clonic seizures

Corneal and palpebral reflex

Corneal and palpebral reflex are not present(temporarily positive corneal reflex after
electrical and penetrative captive bolt stunning

Blinking in response to the stimulus
during testing the palpebral andcornealreflex

Vocalisation

No vocalisation

Vocalisation is possible (cave: not all
conscious animals may vocalise)

Eye movements

Fixed eyes (wide open and glassy eyes withclearly visible iris/cornea in the middle);
obscured eyeballs owing to rotation in the eye
socketEye movements: eye tracking to moving
objects, spontaneous blinking

ABM related to death after application of on-farm killing methods(EFSA, 2020a; EFSA, 2013)

Death needs to be monitored and confirmed repeatedly after applying thekilling method and before disposal of the carcass.
ABM : state of death (pain andfear as welfare consequences)

Outcome dead animals (low risk of pain andfear)

Body movements

Relaxed body, loss of muscle tone

BreathingAbsence of breathing, apnoea

Corneal and palpebral reflex

Corneal and palpebral reflex are not present

Pupil size

Dilated pupil

heartbeatNo heartbeat

Zephyr EXL

Toolboxes (EFSA, 2020a; EFSA, 2013)
EFSA (2020a, 2013) has combined the ABM for the assessment of consciousness
and death in descriptive toolboxes for each procedure.

Zephyr EXL

Thank you for your attention. Do you have any questions?

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info.pigs@eurcaw.eu

EURCAW-Pigs@eurcaw

www.eurcaw-pigs.eu

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