Also see Management of Laboratory Animals.
Animal welfare concerns, as described in the Overview of Animal Welfare, affect all species of animals, including those used for research in laboratories.
Welfare of Animals Used in Biomedical Research
Although the ethics of using animals in biomedical research generates some debate, society has generally considered it acceptable to use nonhuman animals to advance biomedicine if the animal's welfare is maintained and the research is important. A cost-benefit analysis is typically done to determine whether such research should be carried out; however, it should be noted that the costs are borne by the nonhuman animals, and the beneficiaries are humans.
In The Principles of Humane Experimental Technique, by W. M. S. Russell and R. L. Birch (first published in 1959 and subsequently republished), the authors introduced the Three Rs for humane research:
replacement: substitution of nonanimal methods whenever possible
reduction: improvement of experimental design so that fewer animals are needed
refinement: improvement of animal husbandry, reduction of animal stress, and use of other methods to enhance animal welfare
These three principles form the foundation for animal welfare protocols in biomedical research.
Environmental Optimization for the Welfare of Laboratory Animals
Providing an animal with the ability to perform species-typical behaviors improves its welfare. Much research has focused on environmental optimization in the laboratory context and has demonstrated positive effects on the welfare of research animals (1, 2). Simple suggestions for optimization include provision of the following:
hiding places
"walls" within the cage to allow for thigmotaxis
food-dispensing objects
social housing
Some examples of sequelae to poor welfare of laboratory rodents include barbering of another animal's fur or whiskers, cage flipping, and bar chewing.
Environmental optimization should be based on the preferences and motivations of the species in question. Cage size is important; however, a larger cage with no other improvements might not provide a measurable improvement in welfare.
References
Ratuski AS, Weary DM. Environmental enrichment for rats and mice housed in laboratories: a metareview. Animals (Basel). 2022;12(4):414. doi:10.3390/ani12040414
Buchanan-Smith HM. Environmental enrichment for primates in laboratories. Adv Sci Res. 2011;5(1):41-56. doi:10.5194/asr-5-41-2010
