In response to the issues posed in this scenario, the Office of Laboratory Animal Welfare (OLAW) provides the following clarifications:

In this scenario, the PI has misinterpreted OLAW’s significant changes guidance.1 The euthanasia of otherwise usable animals without notifying the IACUC is not responsible animal use. Although OLAW’s guidance states that “The use of fewer animals than approved may be handled without IACUC policy, approval, notification, consultation, or administrative handling”, these actions can be required by the IACUC to not waste animals unnecessarily.1 By eliminating an experimental group, the PI may confound the validity of the research. As the authorized entity to oversee animal welfare, the IACUC can question any aspect of animal use. This includes, as stated in the Guide, “scientific elements of the protocol as they relate to the welfare and use of the animals.”2 The IACUC should consider educating investigators concerning institutional use of unneeded animals and create opportunities for PIs to transfer usable animals to holding or training protocols for future use.