I am not an advocate of firearm stunning of animals in the meat industry. For humane, operator safety and efficiency reasons, I believe captive bolt stunning for beef and electrical stunning for hogs is the best
. Controlled atmosphere stunning for hogs in large plants work well because of economies of scale. However, many small plant operators still prefer using firearms for stunning of livestock.
In October, 2016, I attended the NAMI Animal Welfare Conference. One of the sessions I attended was a presentation by Jennifer Woods on the use of firearms and despite it is not my method of choice, I thought I would share the information presented for operators using this method.
The most common causes of failed stuns are:
· Not the appropriate firearm for the species
· Inaccurate placement of shot
· Wet or damp ammunition
· Failure to maintain gun
A gunshot kills by mass destruction to the brain. First, the shockwaves compress the tissues ahead of the bullet. Second, laceration or crushing along the path or track of the bullet as it travels through the brain takes place. Third, formation of temporary and permanent damage in the brain caused by the track of the bullet.
Ideally, you want the bullet to maintain enough energy to effectively penetrate the skull of the animal, but not so much it passes right through.
As the bullet passes through the air it loses energy. The further it travels, the less energy it has as it hits the target. Therefore, close range shots will not require the same amount of kinetic energy as a longer distanced shot.
Shape of ammunition can also influence energy loss. Pointed bullets have less resistance than rounded bullets, loosing less energy as they travel.
The caliber of the gun is based on the interior bore or diameter of the barrel. The larger the caliber (greater mass) the more suitable it is for:
1. Larger animals
2. Animal with thick skulls or horn mass
3. Longer distance shots
The firearm of gun will be either smooth or rifled (spiral grooves).
When a barrel is rifled, it causes the bullet to spin. The more spin a bullet gets from rifling, the more stable it is in flight making for a more accurate shot, especially from a distance.
Appropriate training is critical to successful firearm stunning.
There are three main considerations when selecting a firearm and ammunition:
1. Size of the animal
2. Thickness of the skull
3. Distance between the shooter and the animal
When choosing between a shotgun and rifle, considerations include:
· Shotguns are best for close range shots (less than 20 feet)
· Only slugs should be used in shotguns
· Shotguns significantly reduce the chance of ricochet
· Rifles are best for longer range shots (greater than 20 feet)
· There is a chance of a ricochet with a rifle
· Ammunition from rifles have a greater chance of passing through the brain and into the neck of the animal. A shotgun slug with the equivalent energy will not
Handling and restraint must be adequate to ensure the safety of the operator and the welfare of the animal.
Preparing to shoot:
· Always be aware of your surroundings – location of people and other animals
· Always shoot with a clear background
· Load your weapon
· Wait for the animal to calm down if necessary. Be patient.
· Have the animal look straight at you
· Find the target on the head
It is also important to keep in mind that in hogs the location of the brain is different in younger hogs as compared to mature animals as illustrated below.
As with all equipment, it is wise to properly maintain firearms:
· Only have enough ammunition out for the current shift (2 per animal)
· Always have a backup gun – rotate usage
· Store ammunition in air tight container
· Regularly clean the gun
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