Those involved in raising animals destined for food recognize disease and accidents are unfortunate realities and that euthanasia under these circumstances becomes a necessity. When end-of-life decisions must be made it’s important that they be carried out in a safe and humane fashion.
Euthanasia is geared to irreversibly obliterate awareness, sensibility and consciousness by disrupting functions of the cerebral cortex and brain stem. The capacity to breathe is lost; cardiac arrest follows. Important cranial nerve reflexes like the corneal reflex, palpebral (eyelid) reflex, pupillary reflex to light, pedal and anal reflex are lost and can be used to assess the level of unconsciousness. Veterinarians can help producers understand how to measure and assess these important reflex activities and ultimately verify death.
In contemplating euthanasia the veterinarian and client must consider the peripheral issues of economics, potential salvage, food safety, welfare, law, human and animal safety, and appropriate disposal of animal carcasses. But ultimately the goal is to humanely induce death with a minimum of pain, fear and distress.
Most commodity groups have incorporated euthanasia in published codes of practice. Though an important first step, a considerable void remains relevant to critical thinking about the issue of euthanasia. David Adams, in a paper delivered on “The biology of euthanasia and humane slaughter” at the International Animal Welfare Conference in Queensland, Australia (2008) put it in perspective: “Applied ethics in the case of animal euthanasia requires the systematic application of informed, structured and disciplined thought in circumstances that impinge on animal distress and suffering. There is always the backdrop of ethical issues that need to be addressed and, ultimately, life and death decisions made that will be judged appropriate.”
There remains abundant room for ambiguity. On one side there is almost universal consensus that suffering animals should be euthanized. Yet the concept of suffering is ambiguous. Most producers consider livestock as assets. Some take liberty with the interpretation of welfare that collides with the belief of those with no connection to the economics of animal production. In particular, there are serious questions about the euthanasia of unwanted animals, of animals whose owners cannot afford veterinary bills, or the mass destruction of animals — especially when the premise for disease control is more political convenience than sound science.
An institutional culture of respect for animal life is critically important in livestock operations. Respect for animal life and the philosophy of compassion described in most guidelines dealing with animal euthanasia should guide the actions of owners and staff. It starts with written, clearly communicated instructions on animal care, up to and including euthanasia. Staff at all levels must be aware of how end-of-life decisions are made and who is responsible for making them.
If veterinarians are not directly involved in performing euthanasia, staff must be properly trained.
Choosing the appropriate method of euthanasia requires consideration of:
- Human safety
The method to be used should not put anyone at unnecessary risk. The potential ricochet of a bullet, reaction of other animals in confined situations and the unpredictability of a falling or thrashing animal must be considered.
- Species and age of animal
- Animal welfare
Animal behaviour and location often limit the choice of euthanasia methods.
Each method requires a differing amount of restraint. Personnel should be skilled in handling animals in an empathetic and firm manner to minimize pain and distress. For example, administration of barbiturate or use of a captive bolt gun requires direct physical contact with the animal, whereas firearms do not. Availability of cattle chutes or other forms of restraint may make certain forms of euthanasia more practical than others.
The situation at hand will dictate the choice of euthanasia method. Euthanasia of a moribund calf in a dairy barn versus euthanasia of a fractious feedlot animal badly injured in a trailer rollover call for very different approaches.
All methods require some degree of skill or training to administer correctly. Animal owners, auction market employees, livestock transporters, and law enforcement personnel should be aware of, and appropriately trained in, at least one emergency euthanasia method.
Some methods require a larger initial investment (e.g., firearms and penetrating captive bolt gun), but are relatively inexpensive to use thereafter.
Some methods appear less objectionable to the untrained eye. Use of barbiturates for lethal injection, for example, may appear more pleasing than firearms. Trained individuals should be prepared to explain differences to untrained individuals observing the act of euthanasia.
The need for diagnostic tissue may become an important consideration. In the event of highly infectious diseases, contamination of premises with blood and tissue during the act of euthanasia or disposal of the carcass needs to be considered.
Understanding the anatomy of the skull and relationship of the brain stem and cerebral cortex to anatomical landmarks is critical. Understanding firearms, choice of calibre, use of penetrating and non-penetrating captive bolts is especially important. Veterinarians and others experienced in euthanasia should be consulted. Published guidelines can be important aids.
— Dr. Ron Clarke prepares this column on behalf of the Western Canadian Association of Bovine Practitioners. Suggestions for future articles can be sent to Canadian Cattlemen ([email protected]) or WCABP ([email protected]).