Well here is knowledge I don’t plan to use any time soon, but in dealing with the realities of farming and animal agriculture in general I received a lesson last week in the proper way to euthanize an animal.
I’ve had to dispatch a few animals myself over the years, and have been around when others have had to put down market
animals or lame horses — whether it was done exactly right or not, the job always seemed to get done. One point underscored a few times at this workshop I attended at the University of Calgary Vet Medicine School is that no body likes to do it but it is a necessary act either in readying an animal for slaughter or to end the life of a sick or injured animal — no body likes to do it, but it is important to do it right.
This workshop was lead by Dr. Jan Shearer, a veterinary researcher with Iowa State University. The objective is to minimize the stress on the animal leading up to the moment of the event, and then to follow through with a procedure that quickly, and effectively causes death.
Shearer recommends three tools that can be used to properly euthanize beef and dairy cattle — 1. A barbiturate such as Pentobarbital, is effective; 2. A gunshot to the head; 3. A penetrating captive bolt (a bolt gun or stun gun). Each comes with some cautions and conditions.
Pentobarbital is a fast and effective barbiturate for euthanization, but the animal has to be caught and given the injection. Particularly when dealing with feedlot cattle or range cattle where catching and restraining can be a major stress on its own, using pentobarbital may not be the best choice. On the other hand for dairy cows use to being in a stanchion or head gate, it may be a good option. The proper dose has to be administered by injection. In a few seconds the animal is unconscious, although it may take several minutes for the heart to stop beating. One important downside to Pentobarbital is that it remains a toxic residue in the tissue so the carcass cannot be disposed of in any manner where it can be found by scavengers such as ravens, eagles, coyotes or grizzly bears, for example, otherwise it is also toxic and lethal to the scavenger. So proper carcass disposal is a key consideration.
Potassium chloride, although it has a place, should never be used as the sole method of euthanasia. It can be used to render an animal unconscious, but is no guarantee of death. So if that method is used then it should be immediately followed with a second step to kill the animal, such as exsanguination (cutting its throat).
A gunshot to the head is probably the most common, easiest and most effective way to euthanize a beef or dairy animal. But use a proper size calibre to do the job. A .32 or .45 calibre handgun is effective. If using a rifle, a .22 magnum or higher calibre gun is recommended. A .22 long range shot is not recommended for adult cattle as it is too light. And if using a shotgun, a .410 to .28 gauge shot gun can be used to euthanize calves, but for mature cattle a 12, 16, or 20 gauge gun is recommended. Number four to six birdshot is effective at a distance of one to three meters.
CAPITIVE BOLT GUNS
In situations where guns can’t be used or aren’t allowed, captive bolt guns — either penetrating or non-penetrating (stun guns) can be used. The penetrating captive bolt gun, positioned properly, delivers a lethal blow, where as the stun gun will render the animal unconscious but then a follow up step, such as exsanguination is needed to kill the animal.
Whether using a fire-arm or a penetrating captive bolt gun, a vital skill is to deliver the blow in the correct spot on the animal’s forehead, says Shearer (see diagram). He says studies have shown that proper point of entry of a bullet or bolt is probably slightly higher on the head than previously believed. On a mature animal the bullet or bolt needs to penetrate between two to four inches to deliver a clean lethal blow. The objective with the gunshot or the penetrating captive bolt is to destroy the animal’s brain stem. If the shot is delivered too high or too low on the head of the animal it can miss the brain stem.
THINGS NOT TO DO
Shearer says there are several unacceptable methods for euthanasia of beef and dairy cattle. They include:
- Manually applied blunt force trauma. Because skulls are thick, knocking then on the head, even a calf, does not achieve immediate unconsciousness and death.
- Injection of chemical agents or substances such as disinfectants, non-anaesthetic pharmaceutical agents.
- Injection of Xylazine or any other alpha-2 agonist followed by KCI or MgS04.
- Air injection into the vein
- Electrocution as with a 120 volt electrical cord
- Exsanguination of conscious animals
A ‘GOOD DEATH’ OBJECTIVE
Shearer says the objective of humane euthanasia is provide “a “good death” whereby life is ended without pain or distress to the
animal. That requires techniques that induce immediate loss of consciousness followed by cardiac and respiratory arrest which results in loss of brain function and death.”
Shearer says the greatest challenge for producers is knowing when to use timely euthanasia. He says no one likes (or wants) to do it, the decision or circumstance of when to do it is not always black and white, and often the fear is of the possibility of acting too quickly — is it time? Might the animal recover?
Quoting a leading American expert on animal welfare, Bernard Rollin a philosopher, who is currently professor of philosophy, animal sciences, and biomedical sciences at Colorado State University, Shearer says when considering timely euthanasia “better a week too early than a day too late.”
Lee Hart is editor of Cattleman’s Corner based in Calgary. Contact him at 403-592-1964 or by email at [email protected]