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Guidelines for Stunning Techniques of Mammalian Food Animals

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1. Cattle

1.1 Mechanical

Important factors:

Note: Together the midbrain and brainstem are responsible for eye movement and body movement, the level of consciousness and maintaining vital body functions, such as breathing and heart rate. (The cerebral hemispheres are associated with higher brain functions.)

The trajectory is especially important when a firearm is used and the shooter may need to be on steps or an elevation to achieve the proper angle. Be aware that the trajectory of the projectile must pass through the midbrain and brainstem (angle is very important). (See [b] below.)

1.1.1 Landmarks and approaches

1.1.1.1 Perpendicular to the front of the head approach
Penetrative Captive Bolt

The intersection of diagonal lines from the middle of the attachment of each horn, or the nuchal crest (the ridge at the back of skull where the neck muscles attach to the head) to the eyes, depending on cattle breed and head shape. The muzzle of the gun should be perpendicular to the front of the skull surface to direct the bolt through the upper brain towards the brainstem. (See [a] and [b] below.)

This is the approach used with captive bolt stunning devices (pneumatic and cartridge fired). This approach is sometimes used with firearms. (See pictures [a] and [b] below.)

Perpendicular to the Front of the Head Approach
[a] Frontal View
Perpendicular to the Front of the Head Approach - Frontal View
HSA
Frontal view of bovine head with landmarks.

foramen magnum
brainstem
and midbrain
[in the centre
of the skull]

[b] Side View
Perpendicular to the Front of the Head Approach - Side View
Legend - Perpendicular to the Front of the Head Approach
Image Description
Landmark and angle relative to the front of the skull when cattle are stunned with either a penetrating captive bolt stunning device or firearm Landmark and angle relative to the front of the skull when cattle are stunned with either a penetrating captive bolt stunning device or firearm. They are discharged perpendicular to the front of the head.
Location of the foramen magnum, brainstem and midbrain in centre of the skull Location of the foramen magnum, brainstem and midbrain in centre of the skull.
Intersection of the diagonal lines indicates the entry point for the bolt or projectile of a mechanical stunning device held perpendicular to the front of the skull Intersection of the diagonal lines indicates the entry point for the bolt or projectile of a mechanical stunning device held perpendicular to the front of the skull.
Non-penetrative Captive bolt

This method requires an extremely accurate aim. As the amount of damage to the skull is reduced, placement of the shot must become precise to achieve instantaneous insensibility. Observations indicate that non-penetrating stunners may be less effective on cattle with woolly heads such as Herefords compared to short haired cattle.

The position of the non-penetrative captive bolt pistol is approximately 20 mm above the position used for the penetrative captive bolt. The animal must be bleed within 30 seconds. The muzzle of the gun must be perpendicular to the front of the skull surface to direct the impact of the blow through the upper brain towards the brainstem.

HSA
Frontal view of bovine head with landmarks for non-penetrative captive bolt that is approximately 20 mm above the intersection of an X formed by diagonal lines from the eyes to the base of the horns.
1.1.1.2 Firearm discharged with the operator standing at ground level in front of the animal

When an animal is stunned with the operator standing at ground level in front of the animal, the entry point of the projectile into the front of the head (skull) must be much lower than what is used with the perpendicular approach, if it is to penetrate the midbrain and brainstem. (See pictures [a] and [b] below.)

In general, it is recommended that the employee to be on steps or an elevation so the firearm shooting can be done perpendicularly to the skull to achieve a better angle more readily. When done this way, the targeted areas will be the same as for captive bolt except for the poll shot which should be used for firearms only (the firearm is the most reliable method to destroy the brainstem from this angle). This angle is for animals with thick skull mass, horns or the frontal shot is difficult to make.

The midbrain and brainstem are the central and lower portions of the brain. They are located in the central and lower portion of the cranial vault [space containing the brain]. (See [a] and [b] below.)

Ground Level Approach
[a] Side View
cow with firearm and projectile aimed at the midbrain and brainstem

[firearm and projectile aimed at the midbrain and brainstem]

[b] Front view
front view of a cow showing the brainstem and the entry point at the front of the head
Legend - Operator Standing at Ground Level
Image Description
Level of the brainstem - in the middle of the skull Level of the brainstem - in the middle of the skull
location of the brainstem and midbrain Location of the brainstem and midbrain - middle of the skull
entry point of the projectile Entry point of the projectile (bullet) if the operator is standing at ground level
indicates the direction that the stunning device should be pointed and the entry point Trajectory of the projectile as it travels to the midbrain and brainstem

1.1.2 Mechanical Stunning Devices

1.1.2.1 Captive bolt
Penetrating Captive Bolt
Animal Calibre Bolt Lengths Muzzle Velocity (ft/s)
Calves .22 Depends on size Depends on size
Steers, heifers, cows .22, .25, .33 12 cm (4 ¾ in.)
or 15 cm (6 in.)
≥ 55 m/s (183 ft/s)
Young bulls .22, .25, .33 15 cm (6 in.) ≥ 72 m/s (236 ft/s)
Mature bulls .25, .33 15 cm (6 in.) ≥ 72 m/s (236 ft/s)
(> 100 m/s preferred)
1.1.2.2 Firearms
Rimfire Rifle Cartridges
Animal Calibre Grain Muzzle Velocity (ft/s) Energy (ft/lb)
Calves .22 S (short)Table Note 1 29 1095 77
Calves .22 LR (long rifle)Table Note 1 40 1255 140
Steers, heifers, cows .22 LR (long rifle)Table Note 1 40 1255 140
Steers, heifers, cows .22 Winchester Magnum 40 1910 324
Bulls .22 Winchester Magnum 40 1910 324

Table Notes

Table Note 1

Do not use hollow point; use solid point bullets. If possible, .22 Magnum recommended for general use to kill livestock over long rifles.

Return to table note 1  referrer

Centrefire Rifle Cartridges
Animal Calibre Grain Muzzle Velocity (ft/s) Energy (ft/lb)
Large Bulls .30 Remington Carbine 110 1990 967Table Note 2

Table Notes

Table Note 2

Upper limit of energy as the projectile may perforate the skull and enter the neck muscle.

Return to table note 2  referrer

Shotgun Shell
Animal Gauge Length Slug Muzzle Velocity (ft/s) Energy (ft/lb)
Large Bulls .410 2 ½ in. 1/5 oz (87 gr) 1830 651
Large Bulls .410 in. 1/4 oz (108 gr) 1800 788
Ammunition
ammunition

1.2 Electrical

Important Factors:

1.2.1 Landmarks and approaches

1.2.1.1 Phase I - Head-to-head
1.2.1.2 Phase II - Head-to-brisket (body)
1.2.1.3 Phase III (Optional)
Recommended Electrical Stunning Parameters - Cattle

Phase I - Head to Head

  1. Check the electrical settings as per the following table.
    Electrical settings
    Amperage Frequency Volts Time
    2.0 - 2.5 50 - 60 Hz 400 4 seconds
  2. Apply current; when insensible (unconscious), start Phase II.

    arrow pointing down to next phase

Phase II - Head to Brisket

  1. Check the electrical settings as per the following table.
    Electrical settings
    Amperage Frequency Volts Time
    3 - 4 50 - 60 Hz 450 4 - 15 seconds
  2. There is less kicking with a longer stun, and/or use Phase III spinal depolarization.

    arrow pointing down to next phase

Phase III (Optional) - Head to Spine

  1. Check the electrical settings as per the following table.
    Electrical settings
    Amperage Frequency Volts Time
    3 - 4 50 - 60 Hz 450 as required
  2. Apply current as required.
Landmarks for electrical stunning
[a]
image of a cow with four indications of landmarks for electrical stunning

2. Swine (hogs, sows, boars, wild boar)

2.1 Mechanical

Important factors:

2.1.1 Landmarks and approaches

2.1.1.1 Market Hog

Intersection of diagonal lines from the midpoint of the attachment of each ear to the medial canthus (middle corner) of the opposite eye. This is approximately 2 ½ cm or 1 in. above the eyes. (See [a] and [b] below.)

2.1.1.2 Sow or boar

Intersection of diagonal lines from the top of the attachment of each ear to the medial canthus (middle corner) of the opposite eye. (See [c] below.)

Note: Regardless of the entry point, the angle of the stunning device with the front of the head must result in a path of the bullet or bolt that will intersect with an internal line from the base of one ear to the other, running through the brain stem. (See [a], [b], [c], [d] and [e] below.)

Frontal View
a] Immature
stunning area for immature pig showing intersection of lines
[b] Immature
stunning area for immature pig showing line running between both ears
[c] Mature
stunning area for mature pig showing intersection of lines and line running between both ears
[d] Market Hog ("non-Yorkshire") Straight front
market hog with arrow pointing to stun site
[e] Mature ("Yorkshire" type) Curved front
mature pig with curved front with arrow pointing to stun site

Note: Breed and age effect on curvature of the front of the head in the side view. (See [d] and [e] above.)

Legend
Image Description
level of the brainstem Level of the brainstem - in the middle of the skull.
location of the brainstem and midbrain Location of the brainstem and midbrain - in the middle of the skull.
intersection of the diagonal lines - entry point for the bolt or projectile Intersection of the diagonal lines indicates the entry point for the bolt or projectile of a mechanical stunning device held perpendicular to the front of the skull.
intersection of the diagonal lines - entry point for the bolt or projectile
Trajectory of the projectile as it travels to the midbrain and brainstem.

2.1.2 Mechanical Stunning Devices

2.1.2.1 Captive bolt
Penetrating Captive Bolt
Animal Calibre (options) Bolt Lengths Muzzle Velocity (ft/s)
Hogs .22, .25, .33 12 cm (4 ¾ in.) ≥ 55 m/s (183 ft/s)
Sows and Boars .25, .33 15 cm (6 in.) ≥ 72 m/s (236 ft/s)
2.1.2.2 Firearms
Rimfire Rifle Cartridges
Animal Calibre Grain Muzzle Velocity (ft/s) Energy (ft/lb)
Hogs .22 LR (long rifle)Table Note 1 40 1255 140
Sows and Boars .22 LR (long rifle)Table Note 1 40 1255 140
Sows and Boars .22 Winchester Magnum 40 1910 324

Table Notes

Table Note 1

Do not use hollow point.

Return to table note 1  referrer

Centrefire Rifle Cartridges
Animal Calibre Grain Muzzle Velocity (ft/s) Energy (ft/lb)
Very Large Boars .30 Remington Carbine 110 1990 967
Shotgun Shell
Animal Gauge Length Slug Muzzle Velocity (ft/s) Energy (ft/lb)
Large Sows
and Boars
.410 2 1/2 in. 1/5 oz (87 g) 1830 651
Large Sows
and Boars
.410 in. ¼ oz (108 g) 1800 788
Ammunition
ammunition

2.2 Electrical

Important factors:

2.2.1 Landmarks and approaches

2.2.1.1 Head-to-head
2.2.1.2 Head-to-body

Option #1: Place two electrodes on the head (see 2.2.1.1) and a third electrode behind the heart on the 4th rib. Current is first directed to the two head electrodes, which is followed by applying current to the head and chest electrodes.

Option #2: Place one electrode on the front of the skull, or on the bony process behind the ear (see 2.2.1.1) and place the second electrode behind the heart on the 4th rib. Current is applied head to chest.

Recommended Electrical Stunning Parameters - Swine
Animal Amperage Volts Frequency Time (sec)
Hogs (head only) ≥ 1.25 > 250-300 50-60 1-3
Hogs (head to body) Head: ≥ 1.25 > 250-300 50-60 1-2
Hogs (head to body) Body: ≥ 1.30 > 300 50-60 3
Sows or Boars ≥ 2.0 > 300 50-60 3

Note: Other voltages, frequencies and times may be used if:

2.3 Controlled Atmospheric Stunning (CAS) (CO2 and Gas Mixtures)

Important Factors:

Stun - to - Stick Interval
First Stop 70-80% CO2
Total Time of Exposure [dwell time] (sec)
Second Stop > 90% CO2
Stick within (sec)
120 30
130 45
140 60
150 75
160 90

Note: Time is counted from last stop just before exiting the gondola.

2.3.1 Carbon dioxide (CO2) and Gas Mixtures

Concentration

  1. It is an OIE requirement that no less than 80% concentration of CO2 be used (90% is preferable).
  2. Exposure time to the gases must be sufficient to ensure no pigs regain sensibility before death occurs due to cardiac arrest or bleeding.
  3. Stun to stick interval must be as per the stun-to-stick interval chart. (Shorter time frames may be required if there are return to sensibility problems.)
  4. Stunning
    • The gas mixture and induction of anaesthesia must be non-aversive and must not be distressing.
    • The chamber and methods of conveyance through it must avoid stress to the animals.
    • The density of animals in the gondola must be such that animals do not fall or lay on each other during the stunning operation.
    • The chamber must be lit.
    • The chamber must be designed so that the animals in the chamber can be monitored at all times by direct observation ports, cameras, or similar means.
    • The chamber must be equipped to continuously measure and display the CO2 concentration (or other gas used in the stunning process) at the point of induction and the maximum concentration.
    • The system must provide visible and audible warnings if the gas concentration falls below the required levels.
    • Stunning must be as per the manufacturer's stunning protocol. See below for alternate stunning procedures. Pigs usually require 3 minute exposure time to the concentrations indicated below.
Controlled Atmosphere Stunning (CAS) - Hogs
Type Method of Stunning Gas(es) Concentration Other Gases
CO2 High blood levels of CO2 (Hypercapnia) CO2 ≥ 80%
90% (preferred)
oxygen, nitrogen, etc.
Gas
Mixtures
Low blood levels of O2 (Hypoxia) O2 ≤ 2% (O2) carbon dioxide, argon, nitrogen
Gas
Mixtures
Low blood levels of O2
and
High blood levels of CO2
O2, and CO2 ≤ 2% (O2)
≤ 30% (CO2)
argon, nitrogen, etc.

Note: Other gas mixtures and concentrations may be used if:

3. Sheep, Lambs, Goats

3.1 Mechanical

Important factors:

3.1.1 Landmarks and approaches

3.1.1.1 Hornless sheep

Hold and discharge the mechanical stunning device so that the bolt/bullet enters the top of the skull at the midpoint of an imaginary line drawn between the animal's ears (See [a], [b] and [c] below.)

[a]
imaginary line drawn between the animal's ears - side view
[b]
imaginary line drawn between the animal's ears - front view
[c]
imaginary line drawn between the animal's ears - top view
Legend - stunning for hornless sheep
Image Description
line connecting the base of the two ears Line connecting the base of the two ears. The midpoint of this line indicates the location of the brainstem in the middle of the skull.
line connecting the base of the two ears Trajectory of the projectile as it travels to the midbrain and brainstem.
3.1.1.2 Horned sheep and all goats
[d]
horned goat - front view with arrow pointing to stun site
[e]
horned goat - side view with arrow pointing to stun site
[f]
horned sheep - side view with arrow pointing to stun site
[g]
horned goat - side view with arrow pointing between horns
Legend - stunning for horned sheep and goats
Image Description
location of the brainstem and midbrain Location of the brainstem and midbrain - in the middle of the skull.
trajectory of the projectile Trajectory of the projectile as it travels to the midbrain and brainstem.
trajectory of the projectile Trajectory of the projectile as it travels to the midbrain and brainstem.

3.1.2 Mechanical Stunning Devices

3.1.2.1 Captive Bolt
3.1.2.2 Firearms

Use the slowest velocity and minimum energy (muzzle) required to effectively stun the animal. (See below).

Firearms for slowest velocity and minimum energy required to effectively stun the animal
Stunning Device Hornless Horned
Captive Bolt Small charge Appropriate charge
Firearm .22STable Note 1 is sufficient .22 LRTable Note 2

Table Notes

Table Note 1

.22 short

Return to table note 1 referrer

Table Note 2

22 long rifle Do not use hollow point cartridges.

Return to table note 2 referrer

Ammunition
ammunition

3.2 Electrical

Important factors:

3.2.1 Landmarks and approaches

3.2.1.1 Head-Only
3.2.1.2 Head-to-Body
Minimal Electrical Stunning Parameters for Sheep, Lambs and Goats
Animal Amperage Volts Frequency Time (sec)
Lambs (shorn) and kids 0.6 250-350 50-60 3
Sheep and goats 1.0 300-400 50-60 3

3.3 Gas, Gas Mixture

These are not commonly used to stun sheep as the wool absorbs a lot of gas, making the system very inefficient.

4. Bison

4.1 Mechanical

Important Factors:

4.1.1 Handling and restraint

4.1.2 Landmarks and approaches

Proper Landmarks for Stunning
Mature males
[a]
mature male bison - side view with arrow pointing to stun site
[b]
mature male bison - front view with indication of the entry point for the projectile
[c]
mature male bison - isometric view with arrow pointing to stun site
Immature Males
[d]
bison immature male - side view with location of brainstem and midbrain indicated and arrow pointing to stun site
[e]
bison immature male - front view with entry point of the projectile indicated
Mature Female
[g]
bison mature female - side view with arrow pointing to stun site
Projectile Entry Point
[e]
bison immature male - front view with entry point of the projectile indicated

[f]

bison skull - top view with arrow pointing to properly located bullet hole
Projectile entry point

Projectile Entry Point

[e]
bison immature male - front view with entry point of the projectile indicated

[h]

bison skull - top view with arrow pointing to properly located bullet hole and imaginary line from the base of one horn to the othe
Projectile entry and imaginary line from the base of one horn to the other
Legend - proper landmarks for stunning bison
Image Description
line from the base of one horn to the other Line running from the base of one horn to the other.
location of the brainstem and midbrain Location of the brainstem and midbrain - in the middle of the skull.
entry point of the projectile Entry point of the projectile (bullet).
trajectory of the projectile Trajectory of the projectile as it travels to the midbrain and brainstem.
arrow indicating projectile entry point Arrow indicating projectile entry point to the skull and brain cavity.
Improper Landmarks for Stunning
Bison Skull
[i]
bison skull - top view with arrow pointing to properly located bullet hole

Note: This is an example of the impact of using improper landmarks. This bison skull contained 10 bullet holes. They were in the front, side and back of the skull. Most of the bullet holes in the front are too low (bovine landmarks), or too much off the midline of the skull (thereby missing the midbrain and brainstem) to be effective.

4.1.3 Mechanical Stunning Devices

4.1.3.1 Captive Bolt

Note: Standard bolts are not long enough for large bulls.

Penetrating Captive Bolt
Animal Calibre Bolt Length Muzzle Velocity (ft/s) Energy (ft/lb)
Immature > .25 > 12 cm (4 ¾ in)
or 15 cm (6 in)
> 72 m/s (236 ft/s) Heavy Charge
Over one year
of age
>.25 15 cm (6 in) > 72 m/s (236 ft/s) Heavy Charge
4.1.3.2 Firearms
  • Perforation and ricochet are a safety concern with high velocity calibre firearms.
  • Use the slowest velocity and minimum energy (muzzle) required to effectively stun the animal.
  • Maximum velocity < 2000 ft/s to help prevent ricochet from the surface of the skull.
  • Maximum energy < 1000 ft/lb to help prevent skull perforation (exiting the opposite side of the skull).
  • Plan the trajectory so that the bullet travels through the midbrain and brainstem, which are located below the horn and between the ears.
  • See 4.1.2 above for stunning problems.
Rimfire Rifle Cartridges
Animal Calibre Grain Muzzle Velocity (ft/s) Energy (ft/lb)
Immature + Cows .22 Winchester Magnum 40 1910 324
Centrefire Rifle Cartridges
Animal Calibre Grain Muzzle Velocity (ft/s) Energy (ft/lb)
Mature Bulls .30 Remington Carbine 110 1990 967Table Note 1

Table Notes

Table Note 1

Upper limit of energy as the projectile may perforate the skull and enter the neck muscle.

Return to table note 1 referrer

Shotgun Shell
Animal Gauge Length Slug Muzzle Velocity (ft/s) Energy (ft/lb)
Mature Bulls .410 2 ½ in 1/5 oz (87 g) 1830 651
Mature Bulls .410 in ¼ oz (108 g) 1800 788
Ammunition
ammunition

5. Horses

5.1 Mechanical

Important factors:

5.1.1 Handling and Restraint

5.1.2 Landmark and approaches

[a] Midbrain and brain stem

head of horse - side view with indication of stun area

[b] Projectile Entry Point

head of horse - front view with indication of stun area and arrow pointing to it

[c] Projectile Entry Point

head of horse - front view with indication of stun area and arrow pointing to it

Legend - landmarks for stunning horses
Image Description
diagonal lines running from the inner corner of each eye to the upper edge of the attachment of the opposite ear diagonal lines running from the inner corner of each eye to the upper edge of the attachment of the opposite ear
diagonal lines running from the inner corner of each eye to the upper edge of the attachment of the opposite ear diagonal lines running from the inner corner of each eye to the upper edge of the attachment of the opposite ear
entry point of the projectile which is approximately one inch above the intersection of the diagonal lines entry point of the projectile which is approximately one inch above the intersection of the diagonal lines
entry point of the projectile which is approximately one inch above the intersection of the diagonal lines entry point of the projectile which is approximately one inch above the intersection of the diagonal lines
arrow indicating entry point into the skull and brain cavity arrow indicating entry point into the skull and brain cavity
location of the brainstem and midbrain - in the middle of the skull location of the brainstem and midbrain - in the middle of the skull

5.1.3 Mechanical Stunning Devices

5.1.3.1 Captive bolt
Penetrating Captive Bolt
Animal Calibre Bolt Lengths Muzzle Velocity (ft/s) Energy (ft/lb)
All horses .22, .25, .33 12 cm (4 ¾ in) 55 m/s (183 ft/s) Appropriate charge
5.1.3.2 Firearms
Rimfire Rifle Cartridges
Animal Calibre Grain Muzzle Velocity (ft/s) Energy (ft/lb)
All horses .22 S Table Note * 29 1095 77
All horses .22 LR Table Note * 40 1255 140

Table Notes

Table Note *

Do not use hollow point.

Return to table note * referrer

6. Cervids (Includes elk, fallow deer, white tail)

6.1 Mechanical (Elk)

Important factors:

6.1.1 Handling and restraint

6.1.2 Landmarks and approaches

"Side" of the head stunning
Female Elk Male Elk
[a]

female elk - side view with indication of stun site

[b]

male elk - side view with indication of stun site

Front or "top" of the head stunning
Female Elk Male Elk
[c]

female elk - side view wirh arrow pointing to stun site

[d]

male elk - side view wirh arrow pointing to stun site

[e]

female elk - front view with intersection of diagonal lines indicating stun site

[f]

male elk - front view with arrow pointing to stun site

Legend - landmarks for stunning cervids
Image Description
diagonal lines running from the inner corner of each eye to the upper edge of the attachment of the opposite ear Intersection of diagonal lines running from the inner corner of each eye to the upper edge of the attachment of the opposite ear.
Indicates the entry point for the projectile on the Indicates the entry point for the projectile on the "side" of the animal's head (temple).
Indicates the direction that the stunning device should be pointed and the entry point when the bolt or projectile is directed towards the Indicates the direction that the stunning device should be pointed and the entry point when the bolt or projectile is directed towards the "top" (front) of the animal's head.
Stunning areas according to sex of animal
Sex Side of the head Front or "top" of the head
Males
  • Midway between the eye and ear, at the eye level
  • Stun perpendicular to the head
  • Easier access from normal standing position
  • OSH issue as can readily perforate the skull
  • Midpoint of the head between the pedicles or antlers
  • Must approach the animal's head from above
Females

OSH Concerns (therefore only use .22 short)

  • Midway between the eye and ear, at the eye level
  • Stun perpendicular to the head
  • Easier access from normal standing position
  • Intersection of diagonal lines from the upper edge of the attachment of each ear to the middle of the opposite eye
  • The stunner operator will have to be high enough to aim the stunning device down to the front or "top" of the almost horizontal head
Best practices include:

6.1.3 Mechanical Stunning Devices

6.1.3.1 Captive Bolt (only from above head, frontal bone approach)
Penetrating Captive Bolt
Animal Calibre Bolt Length Muzzle Velocity(ft/s) Energy (ft/lb)
Female + male .22 Either 55 m/s (183 ft/s) Appropriate charge
6.1.3.2 Firearms
Rimfire Rifle Cartridges
Animal Calibre Grain Muzzle Velocity(ft/s) Energy (ft/lb)
Female .22 STable Note 1 29 1095 77
Female .22 LRSTable Note 2 40 1255 140
Male .22 LRTable Note 2 40 1255 140
Male .22 Winchester magnum
Note: mature males and frontal "top" approach only
40 1910 324

Table Notes

Table Note 1

.22 short (lead round nose)

Return to table note 1 referrer

Table Note 2

.22 long rifle (lead round nose)
Do not use hollow point.

Return to table note 2 referrer

Ammunition
ammunition

6.2 Mechanical (Other Cervids - fallow deer, white tail)

Important Factors:

6.2.1 Handling and restraint - similar to elk

6.2.2 Landmarks and approaches - similar to elk

Frontal bone to the skull is very thin e.g. fallow deer 0.33 - 0.48 cm (0.13 - 0.19  in.)

6.2.3 Mechanical stunning devices

6.2.3.1 Captive Bolt

See elk.

Appropriate light charge (similar to that used for calves and lambs).

Penetrating Captive Bolt
Animal Calibre Bolt Length Muzzle Velocity (ft/s) Energy (ft/lb)
Female + male .22, .25, .33 Either 55 m/s (183 ft/s) Appropriate charge
6.2.3.2 Firearms

See elk.

Rimfire Rifle Cartridges
Animal Calibre Grain Muzzle Velocity(ft/s) Energy (ft/lb)
Female + male .22 STable Note 1 Table Note ** 29 1095 77

Table Notes

Table Note 1

.22 short (lead round nose) Do not use hollow point.

Return to table note 1 referrer

Table Note **

Side of the head not recommended in fallow deer due to the risk of perforation.

Return to table note ** referrer

7. Rabbits

Acceptable methods for stunning rabbits in federal slaughter facilities include captive bolt pistol stunning (penetrative and non-penetrative) and electrical stunning.

7.1 Mechanical (penetrative and non-penetrative)

A non-penetrative captive bolt gun uses a compressed air driven, non-penetrating captive bolt to humanely and effectively stun rabbits of all weights and sizes.

Photograph of a non-penetrative Zephyr captive bolt gun.
Example of a Zephyr gun

A penetrative captive bolt is a spring-fired captive bolt gun which is effective when operated correctly. In some food markets, rabbit meat is sold with the head attached therefore the penetrating captive bolt may not be the most appropriate tool to use due to the force of the stun.

Care needs to be taken when placing the gun against the rabbit's head as the skin over the head of a rabbit is loose and if it slips, it can make the aim inaccurate.

Photograph of a penetrative captive bolt gun.
Placement of captive bolt stunner for mechanical stunning method in rabbits
"X" on forehead (frontal view) and arrow (profile view) indicate target area to place captive bolt stunner.
Schematic diagram of the head of a rabbit in frontal view showing with x where the target area on the forehead should be for stunning with penetrative and non-penetrative captive bolt guns.
Schematic diagram of the head of a rabbit in profile view showing with arrow where the target area on the forehead should be for stunning with penetrative and non-penetrative captive bolt guns.

7.2 Electrical (electronarcosis)

Electronarcosis, using the head-only method, is the more commonly used stunning method in rabbit slaughter facilities when larger numbers of animals are processed.

Rabbit fur is resistant to an electrical current therefore the required stun amperage for an effective stun is 0.14 amps and 100 volts for a period of three seconds or 0.2 amps for at least 2 seconds.

Wetting the rabbit slightly can increase electrical conductivity. However it must not be so wet as to cause part of the stunning current to flow over the surface of the body instead of through the head and the brain.

Rabbits return to sensibility from head only electric stun rapidly; therefore rapid bleeding within 5 seconds is essential to avoid a return to consciousness. When using a transverse incision of the neck, both carotid arteries should be severed for rapid bleed-out.

Example of electrodes for stunning rabbits:

The head of the rabbit is placed into the V of the electrodes which is firmly applied between the back of the eyes and the base of the ears to span the brain.
Diagram of a head-only electrical device for stunning rabbits.
Placement of electrodes for head-only electrical stunning of rabbits.
Side view of rabbit showing with an arrow the proper placement of electrical stunning electrodes to span the brain.
Frontal view of rabbit showing with an arrow the proper placement of electrical stunning electrodes to span the brain.
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