This section provides an overview of the IACUC’s role regarding animal environment, housing and management. The Guide provides recom-mendations that are written in general terms and require the application of sound professional judgment (i.e., current best practices). The use of performance standards, or an outcome approach, will direct decisions to optimizing animal well-being while providing a refined animal model for the researcher. Variances from Guide recommendations in animal care and husbandry should be based on clear scientific justification, or rationale for an alternative approach to accomplish a performance based Guide stan-dard, and must be approved by the IACUC.
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. Well trained and motivated personnel can often ensure high quality animal care, even in institutions with less than optimal physical plants or equipment.
Animals should be housed in a manner that facilitates the expression of species-typical behavior and minimizes stress-induced behaviors. For social species, housing systems should be designed to accommodate pair or group housing of animals. The Guide places responsibility with the IACUC for the review and approval of housing systems; it further recommends follow-up objective evaluations to ensure the housing system is appropriate for the health and well-being of the species and consistent with research objectives.
B.2.b. Animal Environment
Adequate animal husbandry practices and health maintenance are facilita-ted by well constructed and maintained caging or housing systems.
allow for conspecific social interaction within or between enclosures, adequate ventilation, and observation of animals with minimal dis-urbance of them;
provide a safe and secure environment that permits the normal physi-logic and behavioral needs of the animals to be expressed;
enable ready access to food and water receptacles and be constructed of materials that balance the needs of the animal with sanitation; and
be constructed with materials that resist corrosion and withstand chip-ing, cracking or rusting.
Unsealed wood may be acceptable for use as perches or other climbing structures, resting areas, or in the construction of perimeter fences, runs and pens, but wooden items need to be replaced periodically because of wear, damage, and to achieve adequate sanitization.
Cage size requirements/recommendations for most common laboratory animal species are provided by the AWRs and the Guide. Cage com-plexities, vertical height of the cage, and the cage design can influence how an animal uses the cage space provided. The cage must provide sufficient space so that, at a minimum, the animal can turn around and express normal postural adjustments. The animal must have sufficient clean and unobstructed space to move and rest in. Use of wire bottom cages is discouraged for rodents, especially on long-term studies or in larger and older animals, as it may cause foot injury. Use of wire bottom cages should be scientifically justified and approved by the IACUC.
Temperature, Ventilation, Illumination and Noise
Environmental factors can have a profound effect on the health and well being of animals as well as on the outcome of experimental manipula-tion. Temperature, humidity, air pressure differential and air exchange rate, illumination level, and noise levels all may affect animal well being and research results.
The range of daily temperature fluctuations should be kept to a minimum (e.g., ± 2º F) to avoid large demands on the animals’ metabolic and behav-ioral processes. Relative humidity should also be controlled (e.g., 30% to 70%). In general, an air exchange rate of 10-15 changes per hour is con-sidered an acceptable standard.
Light intensity, duration of exposure, wavelength of light, light history of the animal, pigmentation of the animal and other factors should be considered when establishing an illumination level in the animal room.
Because sound exposure can have variable effects on animals, noise gen-erators (e.g., human activities, noisy animals, equipment) should be mini-mized in animal areas. Environments should be designed to accommodate animals that make noise, rather than resorting to methods of reducing the noise made by animals.
A review of an animal care and use program should include consideration of environmental standards adopted for the facilities with adequate justification for deviations, which are reviewed and approved by the IACUC. While en-vironmental control in outdoor facilities is much less stringent, acceptable ranges in temperature for several species are specified in the AWRs. Reliable methods for monitoring environmental control systems should be in place, including an after-hours monitoring and response program. Back-up heating, ventilation, air conditioning, and lighting systems are highly desirable.
It is imperative that research animals be adequately and appropriately identified and that records pertaining to individuals or groups of animals be maintained. A wide range of acceptable identification methods can be employed, including:
The use of toe-clipping to identify individual rodents is discouraged; when necessary, it should be rigorously justified for scientific necessity and done only on very young rodents.
Animal records may consist of a cage card or may involve detailed individ-ual animal information, depending principally on the species and research requirements. Cage cards should include:
source of the animal,
strain or stock,
names and locations of responsible investigators,
pertinent dates, and
All animals should receive food that is:
free from contamination, and
of sufficient quantity and nutritive value to maintain their good health.
Specific diets should be selected based on the needs of each species, with special consideration of the requirements for Vitamin C by guinea pigs and some species of nonhuman primates. Animals should be fed at least once a day except under conditions of hibernation, veterinary treatment, pre-procedural fasts, or other justified circumstances. In some species and in some circumstances, varying the diet by providing “treats” can improve animal health and well-being. However, caution should be exercised that animals do not forsake eating their nutritionally balanced diet for treats.
It is known that standard commercial dry bulk foods, when stored properly, retain their nutritional value for six months (generally three months for those containing Vitamin C, unless a stabilized form is used).
To help ensure that fresh, uncontaminated food is provided:
bags should be stored off the floor,
the milling date should be known (the date or a code is usually stamped on each bag), and
the oldest stock should be used first.
Small quantities of food may be kept in animal rooms if stored in tightly covered, leak and vermin proof containers; these should not be moved from room to room.
Food should be provided in receptacles that are accessible to all animals in a cage or pen and placed so as to minimize contamination. More than one receptacle may be necessary for some socially housed animals. Food receptacles should be easily cleaned and sanitized, and those functions should be performed on a schedule that meets Guide and AWR requirements. With limited exceptions, (e.g., neonatal animals or animals with limited mobility) food should not be placed on the bottom of the cage. Although some species may prefer this presentation, it results in waste and contamination of the food.