Annex A - Species-Specific Stunning Guidelines - Red Meat Species
1. Cattle

1.1 Mechanical

Important factors:

  • Handling and restraint facilities must meet current OIE and industry standards.
  • Cattle, especially mature males with horns, have very thick frontal bones overlaying the brain.
  • Plan the trajectory so that the bolt or projectile travels through the brain (cerebral hemispheres, midbrain, brainstem). The most significant of these are the midbrain and brainstem, which are at the level of the bottom of the attachment of the ears.

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 is at ground level in front of the animal. Be aware that the trajectory of the projectile must pass through the midbrain and brainstem. (See [b] below.)

1.1.1 Landmarks and approaches

1.1.1.1 Perpendicular to the front of the head approach

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 medial canthus (middle corner) of the opposite eye. (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

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
ImageDescription
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.

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.)

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
ImageDescription
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

  • Use the appropriate landmarks. (See 1.1.1.1.)
  • Do not stun from the top of the head or behind the ears, due to the risk of pithing the animal.
  • Discharge the stunning device perpendicular to the front of the head.
  • For class of animals other than veal calves, the bolt length must be at least 12 cm (4 ¾ in.). The bolt length for bulls must be 15 cm (6 in.).
  • Calibres (diameter) available for the cartridge bolts include .22, .25, and .33.
  • The .25 calibre and larger captive bolt stunning devices with heavier charges are far more effective on bulls than the .22 calibre. (Temple Grandin recommends .25 calibre or larger.)
  • Trigger and contact firing options are available.
  • Use the manufacturer's recommended charge, cleaning, maintenance and stunning protocols.
  • Assess bolt velocity by using the manufacturer's bolt velocity testing device, or similar means. (daily)
Penetrating Captive Bolt
AnimalCalibreBolt LengthsMuzzle 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

  • Use the slowest velocity and minimum energy 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/lbs to help prevent skull perforation (exiting the opposite side of the skull).
  • Plan the trajectory so the projectile travels through the midbrain and brainstem, which are located at the level of the bottom of the attachment of the ears. See 1.1 "Important factors" above.
Rimfire Rifle Cartridges
AnimalCalibreGrainMuzzle 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.

Return to table note 1  referrer

Centrefire Rifle Cartridges
AnimalCalibreGrainMuzzle 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
AnimalGaugeLengthSlugMuzzle 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:

  • Handling and restraint facilities must meet current industry standards.
  • Individual animal restraint is required.
  • The electrodes are firmly pressed against the animal until stunning is complete. This is to ensure they remain in contact and to facilitate current flow.
  • A water spray is to be used to improve contact.
  • Immediate post stun sticking is required (before or after hanging on line).
  • OSH provisions required due to high amperage and voltage.

1.2.1 Landmarks and approaches

  • Electrodes are firmly pressed against the top of the head (nuchal crest), the chin and the brisket.
  • A two-stage stunning technique must be used; a third stage may be used if required.

1.2.1.1 Phase I - Head-to-head

  • In this stage a current is sent through one electrode that is firmly pressed against the top of the head (usually behind the nuchal crest) and a second electrode is firmly pressed pressed against the chin. (See [a] below.)

1.2.1.2 Phase II - Head-to-brisket (body)

  • Follows phase I
  • In this stage a current is sent through an electrode firmly pressed against the top of the head and a third electrode that has been firmly pressed against the brisket [heart area]. (See [a] below.)

1.2.1.3 Phase III (Optional)

  • Follows phase II
  • This is an optional phase of electrical stunning in bovine.
  • Current is sent from the electrode pressed against the top of the head to a fourth electrode pressed against the spine.
  • This phase is used to minimize post stun kicking. (See [a] below.)
Recommended Electrical Stunning Parameters - Cattle

Phase I - Head to Head

  1. Check the electrical settings as per the following table.
    Electrical settings
    AmperageFrequencyVoltsTime
    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
    AmperageFrequencyVoltsTime
    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
    AmperageFrequencyVoltsTime
    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
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