ILAR Journal Online, Volume 36(2) 1994: Farm Animals in Biomedical Research

Online Issues

<< All Back-issues

<< This Issue's Table of Contents

ILAR Journal V36(2) 1994 [FORMERLY ILAR NEWS]
Farm Animals in Biomedical Research - Part Two

Issues for Institutional Animal Care and Use Committees (IACUCs)

Commentary: Farm Animal Use in Biomedical Science--Melding the Guidelines^a
Stanley E. Curtis

Stanley E. Curtis, Ph.D., is Professor of Animal Sciences and Head, Department of Dairy and Animal Science, College of Agricultural Sciences, The Pennsylvania State University, University Park.

INTRODUCTION

Biomedical researchers and teachers are turning more and more to using farm animals as model subjects. As organizers of the 1993 meeting in Oklahoma City rightly observed, "The use of farm animals in research and education presents a special challenge to today's scientists, educators, and regulatory agencies? Why? Consider the following two reasons:

There are apparent differences between the standard husbandry practices for animals as outlined in the Guide for the Care and Use of Laboratory Animals (NIH Guide) (NRC, 1985) and in the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching (Ag Guide) (Consortium for Developing a Guide, 1988). These are discrepancies in important aspects of animal care---excrement accumulation, temperature control, pest management, ventilation rate, specifications for surfaces, and even in some cases frequency of observation. Can differences such as these be explained? What are their scientific bases?
Animal activists are satisfied by neither set of guidelines and are especially critical when the two husbandry standards seem to be so disparate. They question how an animal's well-being can be protected by both sets of guidelines. Such criticism has left some biomedical scientists wondering, for example, whether federal policy and law permit them to use animals purchased from farmers who did not follow the biomedical standards of care when the creatures were in their charge.

The purpose of this article is to suggest (1) that the two sets of guidelines used by the scientific community for the care and use of farm animals (the NIH Guide and the Ag Guide) be melded or harmonized, and (2) that the federal government's policies and regulations come to reflect this approach. In this way, farm animals could be cared for in systems ranging from conventional laboratory animal facilities to well-designed, well-managed commercial farms regardless if the research were agricultural or biomedical in nature.

Moreover, the decision whether a facility or university system would be "exempt" from federal inspection--as described by the Animal Welfare Act and its amendments--could be based not on the outcome of the research (whether biomedical or agricultural in nature), but on the specific requirements of the protocol. If the research or education must be conducted in a farm setting to meet its objectives, the protocol would be exempt from inspection.

Two ideas should be kept in mind when considering the differences between the two sets of guidelines, which I hope ultimately will be found sensible and will be adopted. First, the very natures of these special animals we humans domesticated thousands of years ago has made them extremely adaptable to various situations, and, perhaps more importantly, as dependent on humans as humans are on them. Secondly, the different kinds of animal research and teaching that occurs in agricultural science and biomedical science impacts on how the animals need to be maintained.

THE NATURE OF FARM ANIMALS

Farm animals are fundamentally different than most traditional laboratory animals. One of the more obvious examples is that most farm animals are bigger than most laboratory animals. Geometry tells us that the surface-to-mass ratio of a 100 g rat is greater than that of a 100 kg ram, and much greater than that of a 1000 kg bull. Physics then tells us that the rat is more sensitive to hot and cold environments than is the ram and especially the bull. In other words, the thermoneutral zones of the ram and the bull, respectively, are wider than that of the rat. Of course, those livestock and poultry that are small--hatchlings and neonates, for example--are also very sensitive to their thermal surroundings, and farmers go to great lengths to protect these animals from both cold stress and heat stress.

All creatures respond to thermal stressors by moving to a more favorable place; that is, if one is available and accessible. A horse at pasture can use a run-in shed as a sunshade in summer and as a shield against freezing rain in winter. It thus thermoregulates behaviorally. A mouse in a hanging cage has limited mobility, thus limited ability to move to a more favorable place. The mouse needs more protection and more environmental safeguards than does the horse.

Genetics is an additional important consideration. In general, outbred livestock and hybrid poultry are constitutionally sturdier than inbred laboratory animals. In other words, consistent with common observations, mongrels are tougher than purebreds.

DOMESTICATION--A MUTUAL CHOICE

Perhaps the most important factor in the unique nature of farm animals is domestication. We humans have domesticated but a tiny fraction of all the animal species on earth. Why cattle but not antelope? Why dogs but not hyenas? Why chickens but not eagles?

Stephen Budiansky, in his book The Covenant of the Wild: Why Animals Chose Domestication (1992), talks about the extraordinarily high failure rate of the human as domesticator:

Indians kept moose, raccoons, and bears as pets, but not one exists as a domesticated species today. The ancient Egyptians, whose very civilization was based on cattle herding and who were well-versed in the mysteries of animal husbandry, tried but failed to domesticate gazelles, ibex, hyenas, and antelope .... Yet even for this highly developed agricultural civilization, such experiments led to naught. By contrast several thousand years earlier, the very first agriculturists, people who had never built a fence or mowed a hayfield, succeeded in domesticating virtually every animal that even today, more than five thousand years later, occupies a place of importance in our homes and fields. (Budiansky, 1992, p. 23).

A few more instructive insights from Budiansky's book help describe the relationship of humans to domesticated animals:

The urge to turn animals either into things or into people reflects the distance we have traveled in a generation or two. We conveniently alternate between anthropomorphism and blindness. (p. 3)

Budiansky concludes, "The only way out is to recognize that, in an evolutionary sense, domesticated animals chose us as much as we chose them" (Budiansky, 1992, p. 24).

CHARACTERISTICS OF DOMESTICATED ANIMALS

What characteristics made farm animals more amenable to domestication than their cousins in the first place? E.B. Hale listed behavioral characteristics he termed either favorable or unfavorable to domestication (1969). These same traits would also seem a suitable list of favorable or unfavorable characteristics of animals used for research. Hale found the following traits favorable for domestication:

large social groups
social dominance orders
males affiliated with a female group
promiscuous mating
males dominate females
sexual signals involve movements or postures
a critical period in development of the species bond
females accept other young soon after parturition or hatching
precocial young
short flight distance to humans
little disturbed by humans or sudden changes in the environment
omnivorous
adaptable to a wide range of environmental conditions
limited agility

The following behavioral traits, characterized as unfavorable for domestication by Hale, cause difficulties for those who work in laboratory settings with species that never were domesticated:

family groupings
territorial social structure
males in separate groups
pair-bond matings
male must either establish dominance over or appease female
sexual signals provided by color markings or morphological structures
species bond established on basis of species characteristics
young accepted on basis of species characteristics
altricial young
extreme wariness and long flight distance to humans
easily disturbed by humans or sudden changes in environment
specialized dietary habits
require a specific habitat
extreme agility

TRANSLATING KNOWLEDGE INTO PRACTICE

While it seems simple to care for an animal, there are various ways to fulfill its needs and support its well-being. Whether a heifer resides in a laboratory animal facility on the third floor of a medical school in downtown Saint Louis or on the back section of a land-grant college's experimental ranch in the foothills of the Sierra Nevada, she has individual needs to support her well-being. This is the main point supporting the wisdom of goal-oriented performance specifications in animal care as opposed to process-oriented design or engineering specifications.

Additionally, those of us engaged in animal care are in the process of perfecting both our understanding of what constitutes well-being and our grasp of the practical means to support it. This process of discovery involves scientifically studying animals to learn more about their needs and how to meet them. We are fortunate because we already know much about the nature of farm animals, largely because they are crucial to the health and well-being of humans, and indeed to the practice of agriculture all over the world. Still, new perspectives come along, such as Budiansky's (above).

Is it any wonder that farm animals flourish both in biomedical laboratories and on farms and ranches? Is it really surprising that guidelines for the care of farm animals in the two settings4eveloped by people with experience working primarily in either one place or the other--would be different? Once we recognize the natural histories of these wonderful animals, and once we appreciate the different needs of scientists working in the two arenas, is there any reason why the two sets of guidelines could not be melded?

With respect to farm animals, I submit that the two guides are not inconsistent with each other. They deal with special animals, and simply reflect different ranges on a wide continuum of acceptable care situations. The existing differences between the two guides are products of poor communication between the two communities of scientists--the agricultural and the biomedical--responsible for their development. The meeting in Okahoma City in 1993^awas designed to facilitate better communication along this line and begin correcting this situation.

AGRICULTURAL VERSUS BIOMEDICAL RESEARCH AND TEACHING

The meeting organizers alluded to this when they said, "the unique needs of each species may vary according to the study objectives .... "^a

Most biomedical research that uses animals is basic; the animal "model" is used to better understand a target species, usually humans. Variables must be strictly controlled in basic research in order to maintain the integrity of results. However, when humans serve as target-species subjects in clinical studies, significant covariables usually are less rigidly controlled than in basic biomedical experiments, because it is important to know that what is being tested (whether an experiment, drug, or therapy) will produce similar results in a wide variety of settings. Most agricultural research--in particular, those experiments requiring that the animals be kept in real or simulated agricultural settings--is akin to clinical research in biomedical science, in which the target species serves also as the experimental subject. Scientists using farm animals as target-species subjects in agricultural research need to study them under the variable conditions typical of farms and ranches. The reality of these environmental covariables is the reason both clinical medical researchers and applied agricultural investigators must conduct much of their work in real or simulated settings instead of under the more closely controlled, artificial conditions needed by basic scientists in both arenas.

The difference in how a nanny responds to experimental treatments in Gainesville, Florida compared with Ithaca, New York or Pullman, Washington is of interest to goatherders in Florida, New York, and Washington. The responses of this goat in a closely controlled environment, while of great interest to scientists, are less interesting to a goatherder. For this reason, there are agricultural experiment stations scattered all over the country. For the same reason the Ag Guide at one point reads:

In many cases, the facilities in which these animals reside must simulate conditions on commercial farms; otherwise, the results may be biased .... The pertinent systems include range or pasture production in naturalistic settings, various degrees of confinement in certain less extensive production systems, and various degrees of confinement in more intensive production systems, including enclosed housing (Consortium for Developing a Guide, 1988, p. 2).
GRAY AREAS

A political artifact--namely, the food and fiber research exemption in the Animal Welfare Act and its amendments--has created many confusing and contradictory situations. We have let this legislative oddity, which makes no sense at all in terms of animal needs, drive regulatory activity that presumably was originally intended to safeguard the well-being of animals and nothing more.

Do farm animals in biomedical research need to be cared for according to protocols that have evolved for the sound care of laboratory animals in general? In most cases, for supporting animal well-being, I would say, no. Because they are highly adaptable and relatively unfinicky, farm animals will thrive in either setting. However, the particular protocol may require a more closely controlled situation. Apart from any scientific requirements, if an animal's well-being is completely supported in a setting typical of a well-designed, well-managed farm, is there any reason it should be kept under a husbandry system that is known to be careful to an unnecessary extent?

If animals are being used in an experiment that does not deal directly with food and fiber production and thus does not require that they reside in a production setting, should they be exempt from certain laboratory animal care policies and regulations? Consider a hypothetical vitamin known to be problematic in human nutrition but not in the nourishment of pigs. If the National Institutes of Health were funding an experiment in an animal science department in which this vitamin was to be investigated using pigs as models for humans, should the care of the pigs be exempt from certain Animal Welfare Act regulations?

CONCLUSION

If the NIH Guide and the Ag Guide were integrated and published as one, then agricultural scientists and biomedical scientists alike could keep their farm animals in care systems ranging from conventional laboratory animal facilities to well-designed, well-managed commercial farms, satisfied that the animals' well-being was being supported across this wide continuum. The choice of system then could be based on the user's personal preference, the institution's capabilities, or any requirements of the science being done. This approach, incidentally, is much like the one now taken by the National Institutes of Health, Office for Protection from Research Risks. Finally, the U.S. Department of Agriculture's decision whether the facility were "exempt" from federal inspection could be based on whether the research or education must be conducted in a farm setting to meet its objectives.

^aThis article is adapted from Dr. Curtis's keynote address at the workshop Farm Animals: Present and Future Use in Research and Education sponsored by the National Institutes of Health, Office for Protection from · There are apparent differences between the standard husbandry practices for animals as outlined in the Guide for the Care and Use of Laboratory Animals (NIH Guide) (NRC, Research Risks of the U.S. Public Health Service and the University of Oklahoma Medical Center and the open forum Farm Animals: Issues Under the Animal Welfitre Act sponsored by the Animal and Plant Health Inspection Service, Regulatory Enforcement and Animal Care of the U.S. Department of Agriculture at the University of Oklahoma Medical Center, Oklahoma City, 27-29 September 1993.

REFERENCES

Budiansky, S. 1992. The Covenant of the Wild: Why Animals Chose Domestication. New York: William Morrow.

Consortium for Developing a Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. 1988. Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. (Available at a cost of $5.00 each from Association Headquarters, 309 West Clark Street, Champaign, IL 61820. Tel: 1-217-356-3182.)

Hale, E.B. 1969. Domestication and the evolution of behaviour. Pp. 22-42 in The Behaviour of Domestic Animals, E. S. E. Hafez, ed. Baltimore, Md: Williams and Wilkins.

National Research Council (NRC). 1985. Guide for the Care and Use of Laboratory Animals. A report of the Institute of Laboratory Animal Resources Committee on Care and Use of Laboratory Animals. Washington, D.C.: U.S. Department of Health and Human Services. (Single copies available from Office for Protection from Research Risks, Division of Animal Welfare, National Institutes of Health, 6100 Executive Boulevard, MSC 7507, Rockville, MD 20892-7507. Tel: 1-301-496-7163.)