Consistently delivered quality programs of husbandry and veterinary care provide the foundation that enables valid scientific research. For proper management of research animals, the animal care and research staff must be responsible, sensitive to the animals’ health and well-being, well trained in the humane care and use of laboratory animals, highly motivated, experienced, and diligent in performing their duties and responsibilities. Standard operating procedures are valuable, and training and supervision are essential to assure a consistently applied and uniformly high level of animal care. Within research facilities, environmental conditions must be carefully controlled so that, along with conscientiously applied programs of animal care and use, the best possible conditions for conducting research are provided.
The Guide remains the primary reference for information on basic principles and standards for laboratory animal management. Laboratory rodents that are disease- and pathogen-free and that do not possess antibodies indicative of past infection are readily available from commercial vendors. Procuring such animals from high-quality sources, transporting them in filtered shipping containers, and maintaining them in facilities with both physical and procedural barriers to the introduction of infectious agents are effective measures to prevent disease within a colony that may confound or ruin experiments.
For certain studies, particularly those associated with immunity, it has become clear that animals protected from exposure to a broad array of organisms have an immune repertoire insufficiently developed to be suitable. This requires adaptable management programs to maintain and segregate subjects across an expanse of health profiles from axenic and gnotobiotic to those in close proximity or intentionally exposed to and potentially harboring a medley of otherwise undesirable pathogens.
Although there are colonies of some species of primates that are free of most agents that cause infectious disease in these species, many primates used are of feral or wild origin. For this reason, appropriate quarantine, isolation, and conditioning programs are critical, in addition to the program followed in the importers’ facilities.
Cages, pens, or runs should provide adequate space to allow for normal physiologic needs, permit postural adjustments, and meet requirements for species-specific behavior. When possible, compatible groups of social animals should be housed together. Primary enclosures should be constructed of durable materials, easily cleaned and sanitized, and designed for comfort and safety. Static microisolation (filter-top) cages and individually ventilated caging (IVC) systems impede cage-to-cage transmission of infectious agents. However, infection can be transmitted horizontally or vertically from parents to progeny in breeding colonies; naive mice introduced for cross-breeding and back-crossing can perpetuate infection; and experimental mice potentially can be exposed to pathogens via a contaminated environment, shared watering valves, research devices, or when taken to laboratories. Individual ventilation of cages serves to delay deterioration of the environment within the cage and maintain a more consistent and wholesome microenvironment; it also saves space in the facility and can be engineered to minimize odors, allergens, dust, and heat exhausted into the macroenvironment.
Federal law in the USA requires that laboratory dogs have an opportunity to exercise regularly and have sensory contact with other dogs unless restricted by experimental or behavioral considerations. Housing for nonhuman primates must provide social and environmental enrichment to promote their psychological well-being compatible with the experimental and practical constraints of the housing situation. Successful enrichment strategies for nonhuman primates have included pair or group housing; variation in the dietary content and method of presentation; diversification of the internal cage environment with ancillary equipment (eg, perches, swings, or ladders); provision of devices to enhance visual, auditory, or tactile stimulation; and participation in challenging, nonaversive behavioral laboratory studies. Efforts to extend and adapt environmental enrichment practices to other laboratory animal species warrant consideration.
Temperature, relative humidity, ventilation rates, lighting conditions (spectrum, intensity, and photoperiod), gaseous pollutants (eg, ammonia), and noise should be carefully controlled at all times and monitored as appropriate. Unstable environmental conditions can have a profound effect on the comfort, well-being, and metabolism of animals and therefore on the quality of experimental data derived.
In general, air temperature should take into consideration the comfort ranges where human workers perform best of 64–73°F (18–22°C) and be set at +/- 2°F of set point. Ranges to take into consideration for optimal well-being of adapted animals are given in the accompanying table. Emerging evidence suggests that mice, whether adults, neonates, hirsute or not, in particular, have been kept traditionally under cold-stress conditions, especially in IVC, to the possible detriment of colony production and many types of experiments, especially those reliant on the immune system or associated with metabolism or physiology. Experience suggests, however, that mice provided an adequate energy diet and housed socially can compensate via nest building and huddling. Relative humidity should be maintained at 30%–70% for most species and preferably within 10% of the set point.