Laboratory animal husbandry covers three areas: (1) Facilities and operating procedures in facilities, including temperature and humidity, lighting, cage construction and maintenance, cage size, and waste disposal; (2) Animal health and husbandry, including feeding, water, sanitation, staffing, classification and separation, and veterinary care; (3) Transportation, including construction, size, and ventilation of transportation cage, identification of animals, and care in transit.
Animal housing systems should facilitate animal well-being, meet research requirements, and minimize experimental variables. Minimal space requirements are mandated in the Animal Welfare Act and recommended in the NIH Guide. Solid bottom caging, with bedding, is recommended for rodents by the Guide. IACUC review of this aspect of the animal care program should ensure that caging enhances animal well-being consistent with good sanitation and the requirements of the research project. Housing systems should provide sufficient space to allow freedom of movement and normal postural adjustments, contain a resting area appropriate to the species, confine the animal safely, provide easy access to food and water, be well-ventilated, allow the animals to stay dry and clean, and meet the biological needs of the species.
Cages should be sturdy and durable, with smooth impervious surfaces to facilitate servicing and sanitation. The design should allow cage occupants to be inspected without disturbing them. Housing systems should be kept in good repair to prevent accidental injury to the occupants and facilitate sanitation.
Attention should be given to providing appropriate social interactions, opportunities for exercise, and environmental enrichment appropriate to the species.
Animals should be maintained in an environment appropriate to the species. The environment within the cage (microenvironment) can differ substantially from the macroenvironment, or the environment in the room. The magnitude of these differences is largely influenced by cage design. For example, some caging systems for rodents incorporate a microbiological barrier that can expose the animals to significantly higher temperature, humidity, carbon dioxide, and ammonia levels than conventionally housed rodents. Exposure to such conditions can increase the susceptibility of rodents to infectious and toxic agents, and perhaps affect research results.
Recommended levels of temperature and relative humidity for various species have been published. These parameters must be carefully monitored and regulated in animal housing facilities because they can affect animal metabolism and behavior and thus can potentially alter research results. Effective ventilation is a critical factor in maintaining acceptable thermal conditions and in controlling chemical and microbial contaminants, as well as objectionable odors, in the primary enclosure. Consideration must be given to control of relative air pressure in the animal housing areas. For example, areas for quarantine, soiled equipment, experiments using hazardous materials, and primate housing should be maintained under relative negative pressure, with appropriate treatment of exhaust air, whereas clean equipment and pathogen-free animal housing areas should be kept under relative positive pressure.
Sufficient bedding must be provided to keep animals dry between cage changes. Bedding should be absorbent, free of toxic chemicals, biologically inert, and unpalatable. Some types of bedding, specifically cedar and pine, produce aromatic hydrocarbons, which can induce significant alterations in hepatic enzyme systems, and thus can have a major impact on certain types of research. Ground corncob bedding is the most common type of bedding used in the animal care facility.
Room light should be uniformly diffused and should provide sufficient illumination to allow daily observation and care of the animals and safe working conditions for the personnel. Lighting should meet the biological needs of the animals in terms of intensity and periodicity. Albino rats, for example, can develop retinal degeneration even when housed under “normal” light intensities. Timer systems can be used to provide a regular diurnal light cycle; however, timer performance should be periodically checked to insure proper cycling.
Food must be fresh, palatable, uncontaminated with biological or chemical agents, and nutritionally adequate for the intended species. Feeders must allow easy access to food yet minimize contamination by feces and urine. Animals should be given enough food to permit normal growth, maintenance of adult body weight, reproduction, and lactation. Only specially formulated diets should be autoclaved, because these diets contain extra nutrients to correct for loss during the sterilization process. Food should be stored on pallets, racks, or carts and kept in designated restricted areas that are cool, clean, dry and free of vermin. Food containers must not be moved from room to room. Food containers should be properly labeled and include the milling or expiration date.
Clean, fresh water must be available at all times; sipper tubes and automatic watering systems must be inspected regularly to insure their proper operation and must be accessible to immature animals. Empty water bottles should be replaced, not refilled.
Good sanitation is essential to maintaining healthy animal populations. Cages must be washed and sanitized before animals are placed in them, preferably using mechanical cage-washing devices. If cages are disinfected with chemicals, they should be thoroughly rinsed prior to use. Bedding must be changed as often as necessary to keep animals clean and dry. Dirty litter should be emptied in an area other than the animal room to avoid aerosol transmission of infectious agents.
Animal rooms, corridors, and other areas must be cleaned and disinfected often to keep them free of dirt, debris, and biological or chemical contaminants. Unnecessary equipment and clutter should be removed from these areas. Cleaning utensils must not be moved between animal rooms. Deodorizers should not be used to mask animal orders.
Waste disposal is subject to federal, state, and local ordinances. Wastes must be removed regularly and frequently. Infectious, radioactive or chemically hazardous wastes, including animal carcasses, should be placed in appropriately labeled containers for disposal according to institutional policies.
Unnecessary noise can be stressful to animals and should be minimized. Whenever possible, noisy activities, such as cage washing, and other loud equipment should be kept in areas separate from the animal rooms. Please keep noise in the hallways to a minimum.
Animal identification is important to good animal care and science. Permanent individual identification of animals using methods such as tattoos, ear notches, or microchips should be supplemented by identification cards that include such information as stock or strain, vendor, responsible investigator, and protocol number. Individual clinical or research records can include such information as experimental use and pertinent clinical data.
Emergency, holiday and weekend care must be available on a regularly scheduled basis. Emergency contact information should be posted on the door of animal rooms.
National Institute of Health (1985). Guide for the Care and Use of Laboratory Animals. No. 86-23. Washington, DC: U.S. Government Printing Office.
Use of Animals in Biomedical Research: The Challenge and the Response. American Medical Association White Paper. (1988). Copies available from the Department of Comparative Medicine.
NIH. (1986). Office for Protection from Research Risks (OPRR). Public Health Service Policy on Humane Care and Use of Laboratory Animals. (301-496-7005). Washington, DC: U.S. Government Printing Office.
Federal Register. (1989). Animal Welfare Act. Washington, DC: U.S. Government Printing Office.
Recommendations for Governance and Management of Institutional Animal Resources. Association of American Colleges and Association of American Universities. (1985).
The Scientist’s Responsibility for Public Information. Society for Neuroscience. (1979). (301-530-8955).
Report of the AVMA Panel on Euthanasia. (2000). Journal of the American Veterinary Medical Association. 218:669-696.
Guidelines for Animal Surgery in Research and Teaching (Special Report). (1993). American Journal of Veterinary Research, 54(9): 1544 - 1559.
Colloquium on the Recognition and Alleviation of Animal Pain and Distress. (1987). Journal of the American Veterinary Medical Association, 191:1184-1297.
Animal Pain: Perception and Alleviation. (1983). R.L. Kitchell and H.H. Erikson (eds.). Williams and Williams Co., Baltimore.
The Role of Animals in Biomedical Research. (1983). Annals of the New York Academy of Science, vol. 406.
Laboratory Animal Welfare Bibliography. (1988). Scientist’s Center for Animal Welfare, (301-654-6390).