While it may be regarded by some as inhumane or unethical to take any life, mankind, as responsible stewards of animals, is obliged to do so for many reasons: for food, health, population control, to alleviate incurable suffering, etc. Yet beyond the ironies and ethical dilemmas of the right to life versus the right to take life, lies the necessity to destroy life. This entails an enormous ethical responsibility relevant to the times, and also the moral injunction that the method of killing be humane, in other words, causing the least possible distress, physically and psychologically. This injunction implies, therefore, that there is an obligation (as a final ethical responsibility and demonstration of respect for the life that is to be terminated) to utilize the best available method of euthanasia: to induce a painless death. There are also economic and aesthetic considerations and other situational variables which make this an extremely complex issue. When "euthanasia" must be administered, if it is to be humane, there should ideally be no distress: most authorities agree that many methods are far from this ideal and, to date, at best we have only a hierarchy of more or less distressing methods to choose from.
Distress measured in the eyes of an observer, dispassionate or otherwise, has necessarily been a subjective process until quite recent times. Nevertheless, the tools for evaluating the degree of distress in animals being killed and during the intervening period the refinement method and interpretation of results has progressed. It is remarkable that there has been so little application of these tools, particularly electroencephalographs (EEG) but also electrocardiographs (EKG) and measurement of blood pres'sure, to determining first of all which agents or methods are inherently capable of causing painless death and which of them, by modification or insistence upon practical but essential precautions, can be safely and economically adapted to invoke a rapid and painless death. Sound clinical, e.g. corneal blink reflex (for non-dissociative anesthetics), and behavioral observations should not, however, be abandoned in the evaluation process for more "sophisticated" methods. It matters little if the dog's heart is still beating and its blood well oxygenated if it is unconscious.
It was the desire to reinforce and to overcome the blocks of language and geography which prompted the World Federation for Protection of Animals (WFPA), Zurich, to establish an International Working Group on Euthanasia of Dogs and Cats in 1975. The working group is loosely constituted of persons with practical expertise in killing animals and who also have access to laboratory resources for undertaking further research. This reflects the necessity of not only assessing present knowledge and experience but of pursuing those lines of endeavor which analysis suggests will be most rewarding. The objective of the Group is to make recommendations on the subject which can be accepted with some confidence by those who must decide by which method animals in their charge shall be killed. They should also choose by which methods animals in their charge shall not be killed.
In seeking the widest possible audience through publication of this report, the motivation has been less of wishing to instruct or enlighten and more to stimulate response from workers everywhere who have knowledge or experience of the practicalities which could usefully be contributed to the dialogue now in progress. The report, in other words, far from being an end, is merely a fresh beginning.
Carding, T. and Fox, Michael W., "Euthanasia of Dogs and Cats: An Analysis of Experience and Current Knowledge With Recommendation for Research" (1978). ISR. 1.