From the Guide:
“The following topics should be considered in the preparation of the protocol by the researcher and its review by the IACUC: . . . criteria and process for timely intervention, removal of animals from a study, or euthanasia if painful or stressful outcomes are anticipated. “
“Euthanasia may be planned and necessary at the end of a protocol or as a means to relieve pain or distress that cannot be alleviated by analgesics, sedatives, or other treatments. Criteria for euthanasia include protocol-specific endpoints (such as degree of a physical or behavioral deficit or tumor size) that will enable a prompt decision by the veterinarian and the investigator to ensure that the endpoint is humane and, whenever possible, the scientific objective of the protocol is achieved.”