Guide for the Care and Use of Laboratory Animals - Office of ...

56GUIdE FOR ThE CARE ANd USE OF LAbORATORy ANIMALSConsideration of floor area alone may not be sufficient in determiningadequate cage size; with some species, cage volume and spatial arrangementmay be of greater importance. In this regard, the Guide may differfrom the US Animal Welfare Regulations (AWRs) or other guidelines. Theheight of an enclosure can be important to allow for expression of speciesspecificbehaviors and postural adjustments. Cage height should take intoaccount the animal’s typical posture and provide adequate clearance forthe animal from cage structures, such as feeders and water devices. Somespecies—for example, nonhuman primates, cats, and arboreal animals—usethe vertical dimensions of the cage to a greater extent than the floor. Forthese animals, the ability to stand or to perch with adequate vertical spaceto keep their body, including their tail, above the cage floor can improvetheir well-being (Clarence et al. 2006; MacLean et al. 2009).Space allocations should be assessed, reviewed, and modified as necessaryby the IACUC considering the performance indices (e.g., health,reproduction, growth, behavior, activity, and use of space) and specialneeds determined by the characteristics of the animal strain or species(e.g., obese, hyperactive, or arboreal animals) and experimental use (e.g.,animals in long-term studies may require greater and more complex space).At a minimum, animals must have enough space to express their naturalpostures and postural adjustments without touching the enclosure walls orceiling, be able to turn around, and have ready access to food and water.In addition, there must be sufficient space to comfortably rest away fromareas soiled by urine and feces. Floor space taken up by food bowls, watercontainers, litter boxes, and enrichment devices (e.g., novel objects, toys,foraging devices) should not be considered part of the floor space.The space recommendations presented here are based on professionaljudgment and experience. They should be considered the minimum foranimals housed under conditions commonly found in laboratory animalhousing facilities. Adjustments to the amount and arrangement of spacerecommended in the following tables should be reviewed and approved bythe IACUC and should be based on performance indices related to animalwell-being and research quality as described in the preceding paragraphs,with due consideration of the AWRs and PHS Policy and other applicableregulations and standards.It is not within the scope of the Guide to discuss the housing requirementsof all species used in research. For species not specifically indicated,advice should be sought from the scientific literature and from species-relevantexperts.Laboratory Rodents Table 3.2 lists recommended minimum space for commonlyused laboratory rodents housed in groups. If they are housed singlyor in small groups or exceed the weights in the table, more space per