The Three Rs framework — Replacement, Reduction, Refinement — guides laboratory animal welfare. Progress in implementing all three principles is improving outcomes for research animals.
Laboratory animal welfare has improved substantially through implementation of the Three Rs, but progress is uneven across species, institutions and countries. Non-human primates, dogs and cats used in research receive more welfare consideration than rodents, fish and invertebrates despite the latter comprising the vast majority of research animals. Refinement advances including better anaesthesia, analgesia and housing standards have reduced suffering in animals still used in research. The most impactful welfare improvements come from replacement — developing alternatives that make animal use unnecessary — supported by regulatory requirements and public accountability for animal research numbers and purposes.