Veterinary Bioethics and Animal Welfare: For the Common Wealth and Good

(From Complementary and Alternative Veterinary Medicine: Principles and Practice. Allen M. Schoen & Susan G. Wynn eds. St Louis, Mosby 1998)


We live in a complex world. A world of such biological and ecological complexity that the element of uncertainty is as omnipresent as intelligent organization is in Nature’s systems, processes and life forms. Human society is similarly complex, but is not always as intelligently self-organizing as natural ecosystems are. It relies upon various laws and moral codes to maintain functional integrity and the well-being of its members. Advances in the natural (biological and physical) sciences have enabled us to overcome, to some degree, the uncertainty principle, and to give a measure of control over the natural world. But such knowledge is always incomplete and the less we think we know, the more we realize that we can never gain absolute control. Advances in the scientific domain of understanding are considerable, from the advent of pyrotechnology and petrochemistry to nuclear fission and genetic engineering biotechnology.

We have not advanced to the same degree in the science of human awareness and behavior, which is the concern of the discipline of ethics. There are various schools or traditions of ethical questioning, reasoning and discourse, the most relevant of which is bioethics. The science of bioethics considers our role and responsibilities, and the consequences of our activities, products, processes, policies, life-styles, attitudes and values in a much wider scope than other ethical systems. The scope is not limited to considering human rights and interests. Equal and fair consideration is given to all sentient life forms, especially in terms of our demands upon them, and to our impact on the environment and therefore upon them as well as ourselves. Equality of consideration is an animal’s basic right. This does not mean that animals are the same as humans, which is the fallacy of anthropomorphic and anthropopsychic thinking. All animals have the right to humane treatment but not all animal rights are the same as human rights because they have different needs and interests.

Dr. Andrew Fraser was the first veterinarian to recognize the importance of bioethics in veterinary practice and education, which he summarized as follows:

“Bio-ethics: While the most imperative objectives in welfare practice relate to the relief of suffering, the promotion of well-being (or the welfare status of, or within, the animal) is an ethical objective. The 2 terms, welfare and well-being, are not synonymous. Well-being is a condition within the animal; it is a state of good health and harmony between the animal and its environment. Welfare certainly incorporates much of the same, but is chiefly an external system of services (which have the state of well-being as one objective). In other words, welfare is exogenous while well-being is endogenous.

Ethics require that the general well-being of animals, used materialistically, should be ensured by adequate standards of welfare. The latter should be provided during the life span of these animals, however short that life span is permitted to be. This is in full accord with the vocational objectives inherent in veterinary medicine.

Animal bio-ethics is a constitution of integrated ethical principles guiding animal welfare practices and serving to control suffering. The 4 broad principles of bio-ethics have been given as: 1) responsible animal management, with appropriate overall husbandry; 2) provision for physical comfort, basic behavioral function, and animal health; 3) prevention or relief of unnecessary pain or suffering; and 4) use of sentient animal life for fully justified reasons. The role of the veterinarian in these matters is obvious and traditional, and a strong veterinary involvement should continue.”[1]

There are seven Golden Rules that I have identified as the basic principles of bioethics. (See Table I). These are generic in that they are applicable to public policy, personal life-styles and professional and corporate activities. They are therefore relevant to the practice and principles of veterinary medicine. It should be noted that bioethics is a synthesis ethics, and of scientific and empathic knowledge, especially in the fields of ecology and ethology, cultural anthropology and social economics.

Veterinary Responsibilities

Veterinarians belong to a unique professional guild that has considerable empathic and scientific knowledge about animals compared to most other academic and business professions. They therefore have a significant, and yet largely unexplored role in society.

Veterinarians have been a unique association for millennia. As interlocutors between people, animals and nature (pan) their role and knowledge, both empathic, scientific and instrumental, was highly valued by society. Indeed, according to Professor Calvin Schwabe in his book Cattle, Priests and Progress in Medicine,[2] the earliest veterinarians were the priest-healer members of ancient Egypt’s many dynasties. But today fewer farm animals are being given the same individual attention or quality of veterinary care and husbandry that they once enjoyed. There are few veterinary experts with the knowledge of good livestock husbandry, ethology, pasture and range management, and ecological farming practices to advise society in these areas. Their value is no longer recognized and most have been forced out of business along with family farms as the decline in rural communities’ quality of life parallelled the industrialization of western agriculture.

Livestock and Agriculture

While the welfare of farm animals in developed countries is severely reduced by extreme overcrowding and deprivation of natural behaviors in intensive systems of production, their welfare problems in less industrialized countries are of a different order. There, intensive systems are fortunately not yet prevalent (and should be opposed), but poor nutrition, inadequate veterinary preventive and therapeutic medicine, climatic extremes, parasitic diseases, and lack of adequate and uncontaminated water, are all too prevalent. Long journeys to slaughter, often on foot for days, poor handling and slaughter facilities and inhumane slaughter methods also need to be rectified, and market infrastructures improved. The welfare of draft animals likewise needs more concerted attention and enhancement for humane as well as economic reasons.

In most parts of the world it is not cost-effective for the consumer-public to regard meat as a dietary staple. And it is not economically possible to raise large numbers of animals humanely for meat. In poorer countries, as Mahatma Gandhi said, “The cattle of the rich steal the bread of the poor.” The veterinary profession should not be part of this, and needs to acknowledge the public health, environmental and farm animal welfare benefits of reduced meat consumption and vegetarianism, especially for a human population of 5.6 billion that will soon double.

Veterinarians have public health responsibilities and have played a valuable role in helping control zoonotic diseases[3]. But those involved in the livestock industry should be aware of the linkage between high animal fat and protein consumption (including seafoods) and a host of health related problems that add to every western and industrialized nation’s health care burden[4] (see Table II). These can be prevented and even reversed by a change in diet to include more organic fresh fruits and vegetables, high fiber cereals, and less refined foods, sugar, salt, animal fat and protein. As developing countries industrialize, the temptation to produce and consume more animal products should be resisted.

Other Veterinary Services

The veterinary profession in more affluent countries has benefited recently from the boom in the popularity of companion animals (primarily cats and dogs), as has the “pet” food industry. Most veterinarians now practice in this field. Others are meat inspectors or work in livestock disease surveillance and control. And some deal with “exotic” pets, valuable race horses, prized livestock, endangered and rare captive species in zoos and wildlife parks, and with the “vivariums” and primate and other animal breeding and caging facilities of the biomedical technology industry. Many others work for this industry researching and developing new products for veterinarians and human doctors to use on their patients.

Ethics of Drug Use

But most of these pharmaceutical products are not ethical because they have not been subjected to any kind of ethical evaluation, even though they may be considered safe, effective and approved by the government and appreciated by clients. For example, many of these products have lead to the annihilation of invaluable ethnoveterinary and ethnobotanical knowledge in colonially exploited developing countries. And their iatrogenic, economic and ecological consequences have been calamitous, from the overuse and abuse of steroids, antibiotics and growth stimulants, to insecticides like DDT and other organochlorines, and dioxins, chemical fertilizers, fungicides, fumigants, and other harmful agrochemical products. Yet the veterinary profession is still divided over the ethics of using drugs for non-veterinary purposes (like genetically engineered bovine growth hormone) to increase animals’ productivity and “efficiency,” then at the expense of animals’ health and welfare.

New Educational Initiatives, Roles and Services

Do we not need more text and courses in ethnoveterinary medicine[5] in the veterinary teaching curriculum especially in developing countries? Also do we not need more regional Centers dealing with animal (including wildlife) health problems related to environmental pollution, and a Chair in every veterinary college? Marine as well as terrestrial life-forms, many of whom people consume, are contaminated with chemical pollutants that affect their ability to reproduce and resist disease, and pass on similar effects to consumers. Farm animals also become concentrators of a host of agrochemicals and industrial pollutants that are as harmful to them as to consumers. Introductory courses in veterinary ecology or ecoveterinary medicine, along with veterinary ethology, bioethics and animal welfare science and the law need to be included in all veterinary colleges world-wide, and also post-graduate diploma courses for advanced study in these areas.

Veterinarians in both urban and rural areas, especially in developing countries, have a vital public health and humanitarian role to play. According to the World health Organization, rabies is the second most prevalent fatal viral disease next to AIDS. The dog, the closest companion in the lives of millions of people, is the main carrier in third world countries. They suffer abominably and needlessly in these countries as a consequence. Every country should have a post-graduate Center to train veterinarians for urban and rural work in animal control, and welfare. The delivery of vaccines and other essential materials necessitates a much closer, intersectoral cooperation[6] and linkage between the human and veterinary medical professions, especially in developing countries. And no county or state public health authority should be without a full time veterinarian with expertise in disease epidemiology, zoonoses and environmental medicine.

Veterinary Students

Many young people become veterinarians because they like the company of animals, would like to be with them on a full-time basis and administer medicine to them and perform surgery to help relieve and prevent their suffering. But in the course of their education, their initial motivations are challenged, tested and sometimes disparaged so they drop out or conform to serve less idealistic and more conventional if not pecuniary ends.

These ends are never fully questioned by being subjected to ethical appraisal. All students should have the opportunity to do so and all teaching staff should participate. A required course in veterinary bioethics would be responsible for this student-faculty forum that would encourage an atmosphere of openness and trust. Students often fear recrimination for their candor and honesty when their views conflict with their teachers and the establishment and when they elect for alternatives to performing various invasive procedures on healthy animals in their courses? But how else are they to learn, to mature, and for us all to learn from each other if there is not openness and mutual respect?

Inviting a controversial outside speaker, or two speakers with opposing views, is also a Socratic approach, long overdue, to furthering our higher educational system. Monolithic organizations, like monocrop farming and monocultures of mind and taste, proliferate only in an ethical vacuum. Veterinary education has become monolithic, pedantic, overly scientific, mechanistic and reductionistic, just as has the training of human doctors in the conventional tradition of allopathic medicine. The revolutionary prescription therefore is L evolution. An evolutionary revolution in the veterinary curriculum is both timely and ethically imperative.

I say imperative advisedly, because I do not believe that there are any absolutes, in terms of truth or understanding, except compassion and reverential respect for all life. I feel this is an imperative because, as a veterinarian for over 30 years, I am convinced that society and my profession also would benefit immeasurably if the role of the veterinary profession, scientifically, technically and ethically, was better defined, funded and appreciated.

Veterinary Ethical Issues and Dilemmas

The veterinary profession is caught in an ethical dilemma, having to serve the interests of clients and society on the one hand and the interests of the animals on the other. Conflicts of interest and responsibility are not easily resolved without ethical deliberation. However, veterinary ethics boards deal only with professional codes of conduct such as possible malpractice, illegal use of drugs, and unfair competitive advertising.

Within every veterinary specialty there are ethical questions to be raised and various practices and policies to be prohibited or promulgated. Ear cropping and tail docking of dogs; euthanizing healthy “pets”; the breeding of mutant “pets” with semi-lethal and lethal deformities; housing laying hens in battery cages, veal calves and pregnant sows in narrow crates and pens; keeping arboreal primates in hygienic but socially and behaviorally impoverished laboratory cage environments; developing new vaccines and drugs to help livestock production intensify and expand in spite of ecological, public health and economic contraindications. An ethical approach to veterinary education and practice will play a significant role in helping society, which is global in scope, become more humane, compassionate, economically and spiritually viable, and ecologically sustainable.

A few examples of veterinary activities past and present show the importance of applying bioethics to objectively evaluate the risks, benefits and long-term consequences of various activities prior to their implementation. Colonial veterinary services, especially in Africa, have for decades focused on increasing livestock health and productivity. These, along with other aid and development programs in agriculture, like the “Green Revolution,” have replaced indigenous knowledge and effective traditional ways of treating and preventing animal (and crop) diseases with more costly and not always reliable vaccines and drugs and less sustainable agricultural practices. Poor management and overstocking have caused serious environmental degradation, even desertification. And the demise of wildlife and biodiversity have been well documented. The combined loss of biological and cultural diversity, i.e., biocultural diversity, is one of the unforeseen consequences of veterinary participation in increasing livestock populations around the world. But his does not mean that livestock and veterinarians alike to not have significant roles to play in ecologically sound and sustainable agriculture.[7]

This example illustrates the need for inclusion of ecology in the veterinary teaching curriculum, as well as training in cultural anthropology and ethnoveterinary medicine. Veterinary schools in developing countries should pay special attention to these subjects and not unquestioningly adopt western veterinary curricula as the ideal.

A second example is in the area of veterinary ethology. Without a greater understanding of the behavior and social and environmental requirements of animals, veterinary education remains extremely deficient. A purely mechanistic and reductionistic approach to animal health, disease prevention and treatment is inevitable if the “scientific method” is so reductionistic that animals’ emotions, behavioral and socio-environmental needs, psychological stress and well being are neither fully understood nor appreciated. This deficiency in veterinary education is self-evident in the fact that the profession has voiced little concern or opposition to cruel and inhumane intensive methods of livestock production – so called factory farms and feedlots; and livestock handling, transportation and slaughter methods; and until recently has done little to address the plight of primates and other animals kept in impoverished zoo and laboratory environments.

Society, as well as the animals under our dominion, need veterinary experts who can speak impartially but as informed and qualified authorities on how animals should be treated. Every community and every corporation that has any business with animals should have such veterinary experts in their employ who have had postgraduate education in veterinary bioethics, ethology, animal welfare science and the law. And every community and every corporation should aim to meet the highest standards of animal care and be open to consultation, public scrutiny and accreditation with national animal welfare agencies, governmental and non-governmental as the case may be.

International Bioethical Standards

Now with the advent of GATT and the World Trade Organization, the need to harmonize animal health and welfare standards, and environmental, biodiversity and endangered species protection laws and conventions internationally is critically important. Veterinarians are needed in this arena, and every country should have representation in order to prevent unfair trading practices, and certified value-based labelling of products (like “human” and “organic”) capricious technical trade barriers from being set up by countries who refuse to adopt basic standards and codes of animal welfare and environmental and endangered species protection.

Through the Codex Alimentarius, the international standards currently being formulated to establish global food quality and safety, that the veterinary profession has an important role to play. The FDA’s Codex Veterinarius, inspired by the German Veterinary Association for the Protection of Animals, is a promising template for further professional development and authority. Humane, as well as sanitary, slaughter facilities and practices coupled with humane transportation to reduce stress and pathogen proliferation, which is a public health concern, are important Codex considerations. The International Standards for organically certified foods should, with respect to meat, eggs and dairy produce, include reference to animals’ living conditions (notably outdoor access) and to the farming systems themselves, which should be ecologically sound. Livestock, crop production and range management practices should be ecologically integrated since monocrop/monoculture farming is the antithesis of organic agriculture.

Veterinary bioethics would also help in resolving cultural differences in animal use and abuse. As we move toward a more integrated fair trade and world market system, cultural differences in attitudes toward animals and in their treatment will be more apparent to the public eye. It is fair to say at this time that while some countries have better animal and environmental protection laws and enforcement than others, no country is without some traditional or commercial form of animal exploitation that does not cause unjustifiable suffering and which is ethically unacceptable.

Animal Health and Well-Being

Veterinary education includes many different disciplines, all of which need to be integrated since the best approach to animal health and welfare is interdisciplinary or ‘holistic’ since most animal diseases are multifactor and pluricausal.

Health is not the absence of disease but a state of harmony or homeostasis between mind and body (psyche and soma) and between the animal and its social relationships. Applied animal ethology is relevant in understanding “ethostasis”, where the animal is in harmony in terms of its ethos or intrinsic nature and behavioral needs.

The animal’s ethos is linked with its telos, its final end or purpose. This telos (see Fig. 1) in instrumental terms is the animal’s place or role in the environment or ecosystem (the ecos) to which it is biologically pre-adapted. Applied veterinary ecology seeks to provide optimal environments that satisfy the animal’s ethos (or behavioral needs), and from a very practical sense seeks to maximize the ecological utility of farm animals in sustainable agricultural systems. Hence, from a scientific as well as an ethical perspective keeping animals in intensive confinement systems that ignore the animals’ ethos, telos and ecos, are unacceptable. The flawed thinking of changing the animal to fit the system must be challenged and environments designed to better fit the animals’ health and behavioral needs. The same criticisms can be leveled at the way animals are kept in most zoos and laboratory animal research facilities.[8]

From the more holistic perspective of veterinary ecology we can say that healthy soils mean healthy crops and forages which in turn mean healthier animals (and people). Nutrient deficiencies in soils, exacerbated by misuse of agrochemicals and poor farming practices (especially monoculture/monocrop farming) increase crop vulnerability and livestock susceptibility to disease, which in turn lead to overuse and misuse of pesticides and veterinary medicines.

For example, a nutrient deficiency of zinc, selenium or vitamin E will impair an animal’s immune system. Overcrowding, poor stockmanship, fear, contaminated water and heat stress are some of the many other factors that will increase an animal’s susceptibility to disease. In immunocompromised animals, bacteria can mutate and become more virulent, increasing the spread of disease. often compounded by parasitic infestation and viral and mycoplasma infections.

The “four pillars” of holistic veterinary preventive medicine are, therefore, right environment, right nutrition, right attention and understanding (i.e., good stockmanship), and right breeding, since heredity plays an important role in stress and disease resistance. But no matter how well the animals are fed, bred and housed, the quality of their relationship with their caretakers and the attitude and understanding of the latter[9] toward them is the ultimate determinant of their well being.

Attitude of Animal Caretakers

Several studies have revealed how a positive affectionate social bond with animals helps enhance disease resistance in laboratory animals. This phenomenon is also apparent in the health and productivity of farm animals and the trainability of dogs and other species.

When animal caretakers express a positive attitude toward farm animals, and when the animals under their care are not afraid of humans, sows have more piglets, hens lay more eggs and cows produce more milk. Meat quality and growth rates in broilers, piglets and beef calves are also better when there is a strong social bond with caretakers.[10]

However, agribusiness ignores this evident fact in favor of the cost-savings of developing large-scale, labor-saving, intensive livestock and poultry systems, where one person is in charge of hundreds, even thousands of animals and of using drugs to make animals productive and less prone to disease. You can argue that a good stockperson with a positive attitude toward animals on a large factory farm will do a better job than one who is indifferent or whom the animals fear. However, working in large intensive production systems will adversely affect the behavior and attitudes of stockpersons. One noticeable difference is more aggressive behavior towards animals which reduces their productivity and overall well being,[11] but not to such a degree that such systems are not profitable anymore.

Animals have served us in myriad ways over millennia and we owe them a great debt of gratitude. We have yet to fully express this gratitude in a more compassionate, egalitarian and mutually enhancing symbiosis. The bond we share with animals today is primarily one of domination and exploitation rather than of service and communion. This bond is even shifting toward one of “genetic parasitism”, where human genes are being incorporated into the genomes of animals. Such transgenic creatures being developed to serve as models for various genetic and developmental disorders in humans, to be blood and organ donors, and to produce “humanized” milk and various pharmaceutical products.[12]

Scientific research is rediscovering the many human benefits of a strong human-animal bond. I prefer to call it the human-non-human animal bond, since we humans are animals after all. Other animals have been shown in a variety of documented studies to help people overcome great emotional difficulties and physical and psychological handicaps.[13] So, we should reciprocate and help them, as by saving endangered species, by restoring and protecting their habitats, and by alleviating and preventing the suffering of animals through the combined efforts of veterinary medical science and bioethics.

Table I

  1. Bioethics Seven Golden Rules
  2. Compassion
  3. Reverential Respect
  4. Ahimsa (avoid harm/injury)
  5. Social justice and trans-species democracy (equal and fair consideration)
  6. Eco-justice/environmental ethics
  7. Protect and enhance biocultural diversity

Table II


GASTROINTESTINAL - Constipation, Hiatus hernia, Appendicitis, Diverticular disease, Colorectal polyps, Crohn’s disease (regional ileitis), Celiac disease, Peptic ulcer, Hemorrhoids, Ulcerative colitis.

CARDIOVASCULAR - Coronary heart disease, Cerebrovascular disease (stroke), Essential hypertension, Deep vein thrombosis, Pulmonary embolism, Pelvic phleboliths, Varicose veins.

METABOLIC - Obesity, Diabetes (type II or noninsulin dependent), Cholesterol gallstones, Renal stones, Osteoporosis, Gout.

CANCER - Colorectal, Breast, Prostate, Lung, Endometrium, Ovarian

AUTOIMMUNE DISEASES - Diabetes (type I or insulin dependent), Autoimmune thyroiditis

OTHER DISORDERS - Allergies, Immunoinsufficiency, Infantile hyperactivity, Migraine, Multiple sclerosis, Pernicious anemia, Rheumatoid arthritis, Spina bifida, Thyrotoxicosis

Modified after D.P. Burkitt in Western Diseases: Their Dietary Prevention and Reversibility. N.J. Temple and D.P. Burkitt (eds). Totowa, New Jersey. Humana Press. 1994.

POSTCRIPT TO THIS CHAPTER (Not included in the original text).


Veterinary bioethics calls on every veterinarian to apply the bioethical principle of compassionate care in their treatment of animal patients and in the advice given to client-owners and care-givers. This helps override the situational ethics of treating animals kept as commodities on factory farms where optimal care of animals on an individual basis is not normally provided for reasons of cost; and where a companion animal is not given optimal care because the owner is of limited financial means or does not feel that the animal is worth the expense of costly diagnostic and treatment procedures.

Rather than compromising their professional standards and integrity in such situations, veterinarians have a moral obligation to advocate compassionate care regardless of the context and situational ethics in which their services are required. This is because the bioethics of compassionate care, which is based on sound science and empathy, balancing objective reason and subjective/intuitive feeling, is a fundamental human responsibility and every animal’s basic right. Furthermore, compassionate care is vital to animals’ health, welfare, and physical and psychological well- being. It is therefore as essential a component of holistic, integrative, and preventive veterinary medicine as is caring for the land a vital aspect of sustainable agriculture.

Other professions and business enterprises are similarly being called to accountability and responsibility, just as all of us in our personal lives must find ways to cause less harm to the natural world and to animals domesticated and wild, in the process of satisfying our basic needs. To realize the long term benefits of applying bioethics in our decision-making and consumer-choices, to our own health, to the economy, and to the entire life community of the Earth, means living mindfully, and by the guiding principle of compassionate care.

No new laws, government oversight, or international conventions can equal the profound benefits that will come from the incorporation of bioethics into the veterinary and medical teaching curricula, and into every level of society.

[1] A. Fraser (1991) p. 932 in Merck Veterinary Manual. Rahway, NJ: Merck & Co.

[2] 1978, Minnesota, University of Minnesota Press.

[3] for example see C. Schwabe Veterinary Medicine and Human Health 3rd Edn. (1984), Baltimore, Williams and Wilkins.

[4] For extensive documentation see N.J. Temple and D.P. Burkitt (1994) Western Diseases: Their Dietary Prevention and Reversibility, Totowa, New Jersey, Humana Press.

[5] For example, see Ethnoveterinary Medicine in Asia, International Institute for Rural Reconstruction, Y.C. James Yen Center, Silang Phillipines (1995) and C.M. McCorkle et al. (eds), Ethnoveterinary Research and Development, London, Intermediate Technology Publications (in Press).

[6] See C.M. McCorkle, Intersectoral Health care Delivery in Alternative Perspectives on Health: An Ecological Approach, J. Chesworth (ed.), Thousand Oaks, California, Sage Publications. (1995).

[7] See Fox, M.W., (1992), The Place of Farm Animals in Humane Sustainable Agriculture, Washington, D.C., The Humane Society of the United States, and C.M. McCorkle (ed.), (1992), Plants, Animals and People: Agropastoral Systems Research, Boulder, CO, Westview Press. Bayer, W. Waters-Bayer, A. (1989), Crop-livestock Interactions for Sustainable Agriculture, Gatekeeper Series Briefing Paper, Sustainable Agriculture Programme, London, International Institute for Environment and Development. Bostid/NRC, (1991), Microlivestock, Little-known Small Animals With a Promising Economic Future, Washington, D.C., National Academy Press for the Board on Science and Technology for International Development, the National Research Council.

[8] See M.W. Fox (1986) Laboratory Animal Husbandry: Ethology, Welfare and Experimental Variables, Albany, New York, State University of New York Press.

[9] For an excellent text for animal caretakers, see R. Kilgour and C. Dalton (1984), Livestock Behavior: A Practical Guide, Boulder, CO, Westview Press.

[10] For a comprehensive review of this fascinating and important aspect of the human-animal bond, see P.H. Hemsworth, et al. (1993) The human-animal relationship in agriculture and its consequences for the animal. Animal Welfare (Universities Federation for Animal Welfare)2:33-51.

[11] For details, see J.F. Seabrook (1994) The effect of production systems on the behavior and attitudes of stockpersons. pp. 252-8 in Proc. 4th Zodiac Symposium. Biological Basis of Sustainable Animal Production. EAAP. Publ.. No. 67. Waneningen, The Netherlands.

[12] See M.W. Fox (2004) Killer foods: When Scientists Manipulate Genes, Better is Not Always Best. Guilford CT. The Lyons Press.

[13] For a recent comprehensive review, see A.T.B. Edney (1992) Companion animals and human health. Veterinary Record, April 4, p. 285-87.