What are the three Rs in laboratory animal welfare?

• A. Replacement, Reduction, Refinement.
• B. Repetition, Reduction, Regulation.
• C. Replacement, Reduction, Regulation.
• D. Replace, Reduce, Refine.

Answer: (C)

The three Rs guiding humane use of animals in research are Replacement, Reduction, and Refinement. Replacement means using non-animal methods or less sentient systems whenever possible, such as in vitro tests, computer models, or using tissues instead of whole animals. Reduction focuses on designing studies to obtain the needed information with fewer animals, through proper statistical planning, power analyses, and sharing controls when feasible. Refinement means altering procedures to minimize pain, distress, or suffering, including better anesthesia and analgesia, humane endpoints, improved housing, and thorough staff training.

Regulation is governance and oversight, not one of the three welfare principles. Repetition is not a term used in this framework. Replace, Reduce, Refine conveys the idea in a similar spirit, but the standard wording is Replacement, Reduction, Refinement.