Refinement — the third R of humane research — focuses on minimizing pain and distress in animal experiments. Modern laboratory animal science has developed a robust toolkit for improving the welfare of mice and rats in research.
Laboratory rodents experience pain and distress from both experimental procedures and the housing environment. The welfare case for refinement is reinforced by scientific evidence that stressed animals produce more variable data, compromising research quality. Inconsistent analgesia, barren cages, and stressful handling all impair the validity of biomedical research as well as the welfare of individual animals. Adopting refinement best practices — positive reinforcement training, environmental enrichment, validated pain assessment, and multimodal analgesia — improves both animal welfare and the quality of science.