Guidelines for Stunning Techniques of Mammalian Food Animals
1. Cattle
1.1 Mechanical
Important factors:
- Handling and restraint facilities should be appropriate to avoid movement of cattle during stunning.
- 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 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
foramen magnum
brainstem
and midbrain
[in the centre
of the skull]
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. They are discharged perpendicular to the front of the head. | |
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. |
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.
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
Image | Description |
---|---|
Level of the brainstem - in the middle of the skull | |
Location of the brainstem and midbrain - middle of the skull | |
Entry point of the projectile (bullet) if the operator is standing at ground level | |
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)
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
- Muzzle (kinetic) energy is frequently used as an indicator of a bullet's destructive potential
- The heavier the bullet and the greater its velocity, the higher its muzzle energy and capacity for destruction of objects in its path
- Selection of an appropriate bullet and firearm is critical to good performance when conducting stunning or humane killing
- Lighter weight, higher velocity bullets can have a high muzzle energy but decreased penetration which can be an issue when penetrating thick bones
- 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 (muzzle) < 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.
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.
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.
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 | 3 in. | 1/4 oz (108 gr) | 1800 | 788 |
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
- 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 - Apply current; when insensible (unconscious), start Phase II.
Phase II - Head to Brisket
- Check the electrical settings as per the following table.
Electrical settings Amperage Frequency Volts Time 3 - 4 50 - 60 Hz 450 4 - 15 seconds - There is less kicking with a longer stun, and/or use Phase III spinal depolarization.
Phase III (Optional) - Head to Spine
- Check the electrical settings as per the following table.
Electrical settings Amperage Frequency Volts Time 3 - 4 50 - 60 Hz 450 as required - Apply current as required.
Landmarks for electrical stunning
- Date modified: