Who should approve the number of animals to be purchased for a study according to the protocol?

• A. The researcher
• B. The IACUC in the protocol
• C. The veterinary staff
• D. The purchasing department

Answer: (B)

The key idea is that animal numbers used in a study are approved through the protocol review process by the IACUC. The researcher can propose how many animals are needed and justify that number with study design and, often, a power analysis, but the final approval rests with the IACUC. They review to ensure the number is scientifically justified, aligns with the 3Rs (reduction, refinement, replacement), and is the minimum necessary to achieve valid results while protecting animal welfare. The veterinary staff contribute input on health and welfare considerations, but they do not authorize the number of animals. The purchasing department handles procurement logistics, not ethical approval.