Performance-Based Criteria as the Basis for Determining Laboratory Animal Housing Standards

The American Association for Laboratory Animal Science (AALAS) endorses the use of performance based criteria as the main determinant in establishing the standards of housing for animals housed within the research environment.

AALAS is an organization, formed in the early 1950’s, whose members provide the care of laboratory animals in the research environment, oversee the use of those animals in research, and perform a myriad of other duties associated with the animal care and use program of any institution, whether it be academic, pharmaceutical, contract, or government. Indeed, the members of AALAS have been intimately involved in the formulation of the initial and each succeeding edition of the Guide for the Care and Use of Laboratory Animals (The Guide).

Designing animal facilities that provide the basic needs of shelter, food, water, and a degree of environmental stability has long been appreciated. It is recognized that science has an ethical responsibility to house animals according to their species-specific needs. (1)

In the Introduction of the current Guide, it charges users of research animals with the responsibility for achieving specified outcomes but leaves it up to the individual institution as to the method of achieving that outcome. “This ‘performance’ approach is desirable because many variables (such as the species and previous history of the animals, facilities, expertise of the people, and research goals) often make prescriptive (‘engineering’) approaches impractical and unwarranted. Engineering standards are sometimes useful to establish a baseline, but they do not specify the goal or outcome (such as well-being, sanitation, or personnel safety) in terms of measurable criteria as do performance standards”. (2)

The Guide states “Proper housing and management of animal facilities are essential to animal well-being, to the quality of research data and teaching or testing programs in which animals are used, and to the health and safety of personnel. A good management program provides the environment, housing, and care that permit animals to grow, mature, reproduce, and maintain good health; provides for their well-being; and minimizes variations that can affect research results. Specific operating practices depend on many factors that are peculiar to individual institutions and situations”. (3)

Performance criteria use the professional input and judgment of the laboratory animal veterinarians and the animal care staff – those individuals with the most intimate knowledge of the needs of the animals within their care. The performance approach defines an outcome in detail and provides the criteria for assessing that outcome. This approach does not limit the methods by which the outcome is achieved.

All of these statements are even more applicable in today’s constantly changing research environment.

AALAS applauds the belief that the recommendations of The Guide should be based on published data, scientific principles, expert opinion, and experience with the methods and practices that have proved to be consistent with high-quality, humane animal care and use. When published scientific data are not available, recommendations in The Guide that are based on expert opinion and experience should be those opinions and experience that are widely accepted by the laboratory animal use community as beneficial to the humane care and use of those animals.

The performance approach defines an outcome in detail and provides the criteria for assessing that outcome. This approach does not limit the methods by which the outcome is achieved.

Species-adequate housing conditions are not only a safeguard for the wellbeing of the animals, but they also are a prerequisite for sound scientific methodology. Inadequacy of animal care (housing) can skew scientific findings and render the particular research useless. “Good husbandry minimizes variations that can modify an animal’s response to experimentation”. (4)

Cage size itself is so variable in studies of environmental effects on animal well-being that comparisons involving other factors can be clouded. For example, the standard cage sizes most commonly used for rodent housing in the United States do not match the standard rodent cage sizes in Europe.(5). The additional space is intended to allow for the addition of structural elements to enable animals to express their typical behaviors, which may help to minimize stress. In contrast to these European regulations, recent publications from groups in the United States suggest that less space might be beneficial for mice.

While engineering criteria may also use the professional input and judgment of laboratory animal veterinarians and the animal husbandry staff, the reference point provided by engineering criteria should only provide guidance especially if there is minimal evidence to support a single reference value or when there is not sufficient data to support it application across all strains and across all situations in individual research facilities. A strict engineering approach does not provide for interpretation or modification in the event that acceptable alternatives are available or unusual circumstances arise. Flexibility around the reference point is essential to allow for these potential alternative approaches and should be based on the professional judgment of those charged with providing optimal housing for the animals, the facility veterinarians, the husbandry staff, and the institutional animal care and use committee.

The creation of engineering criteria for each species of animals used or that could be potentially used in a research environment would be a daunting if not an impossible task. Coupled with this seemingly limitless list of potential species that would merit consideration is the unique environment of each institution conducting research and the unique requirements of each individual research project. Dealing with the uniqueness of institutions and of individual research projects is the responsibility of the institutional animal care and use program as described in Chapter 1 of The Guide: “Proper care, use, and humane treatment of animals used in research, testing, and education require scientific and professional judgment based on knowledge of the needs of the animals and the special requirements of the research, testing, and educational programs”.(6)

References

1. Wolfe, Thomas L, “Environmental Enrichment”, ILAR Journal, Vol. 46, No. 2, 2005, p 80
2. The Guide for the Care and Use of Laboratory Animals, Institute of Laboratory Animal Resources, National Academy of Science, 1996, p. 3
3. The Guide for the Care and Use of Laboratory Animals, Institute of Laboratory Animal Resources, National Academy of Science, 1996, p. 21
4. Reinhardt, Viktor and Reinhardt, Annie, Comfortable Quarters, Animal Welfare Institute, 2002, p. ii.
5. Benefiel, Ann C., Dong, Willie K., Greenough, William T., “Mandatory ‘Enriched’ Housing of Laboratory Animals: The Need for Evidence-Based Evaluation”, ILAR Journal, Vol. 46, No. 2, 2005, p 96
6. The Guide for the Care and Use of Laboratory Animals, Institute of Laboratory Animal Resources, National Academy of Science, 1996, p. 8