Oregon State University

IACUC Policy for End-Stage Illness and Pre-emptive Euthanasia based on Humane Endpoints

Compliance with all governing regulations involving humane care and use of animals in research is mandatory at the Oregon State University.  Legal, ethical, and regulatory guidelines obligate all personnel involved with research protocols utilizing animals to ensure that animal pain, distress, and suffering is minimized.  Therefore, the Institutional Animal Care and Use Committee (IACUC) discourages studies allowing death without intervention (“death-as-an-endpoint”) for humane reasons, and encourages, when feasible, the development and inclusion of humane endpoints to define when pre-emptive euthanasia will be employed.

The IACUC and the Attending Veterinarian generally require investigators to humanely euthanize all moribund animals, rather than allowing them to die without intervention.  Euthanasia methods must be in compliance with the current AVMA Guidelines on Euthanasia and approved by the IACUC.  For studies in which death without intervention is proposed, justification should be provided to the IACUC.  Inconvenience is not reasonable justification. 

Investigators are obligated to make every effort to identify and humanely euthanize moribund animals, including weekends and holidays. Moribund animals will be humanely euthanized by the Attending Veterinarian, or designee, if laboratory staff cannot be contacted.

Humane endpoints are criteria developed to avoid or terminate unrelieved pain and/or distress.  These are intended to not disrupt the integrity of the study.  Once a humane endpoint is reached, the animal should be immediately euthanized or treated as outlined in the protocol.

End-stage illness is defined as a debilitating physical state where death is imminent and treatment ineffectual.  Animals exhibiting either severe signs of morbidity or a moribund state would constitute an end-stage illness.  Investigators should feel confident in judging the condition of their animal subjects, differentiating between a morbid and moribund animal, and agree to perform approved euthanasia when necessary.  The following lists will aid investigators and laboratory personnel in identifying morbid and moribund animals.  In addition, for experiments involving tumor bearing animals, the OSU Tumor Burden Scoring Guidelines, for the applicable species, should be used.  If there are any questions or concerns about judging the condition of animal subjects, please contact the Attending Veterinarian or designee.

Morbid state is a condition relating to, or typical of, disease or illness.  Any animal exhibiting a sign of morbidity should be reported immediately to the LARC veterinary staff. 

Moribund state is defined as a state of dying.  Any animal exhibiting these characteristics would be considered to have end-stage illness and should be euthanized immediately. 


To summarize, all investigators and laboratory personnel utilizing animals in research need to be cognizant of the well-being of their animals. The health and well-being of research animals should be monitored at least once daily.  Investigators, in consultation with the Attending Veterinarian, or designee, need to define the expected clinical signs that will be observed and describe the progression and an appropriate endpoint for animals expected to become moribund. Once clinical signs are observed, animals must be monitored and euthanized by the laboratory personnel, as described in the IACUC approved Animal Care and Use Proposal (ACUP).  Any questions or comments should be directed to the IACUC Office at 541-737-2762.

To provide assistance in complying with this policy, the following information is provided as clinical signs that may be monitored to assist the PI in development of an ACUP description of the procedures that will be employed. Not all signs listed below will apply to all species or projects. Consideration of the clinical signs to be observed should reflect the species and the research objectives.

The following are signs for evaluating morbidity in animals:

  • Hunched posture
  • Sunken eyes, with or without discharge
  • Respiration that has increased, decreased, or appears labored
  • Rapid weight loss (more than 10% of body weight)
  • Decreased or no intake of food
  • Hypothermia or hyperthermia
  • Ruffled hair coat or feathers, erection of hair, fur, or feathers, lack of grooming behavior
  • Diarrhea or constipation
  • Vomiting
  • Unsteady gait or lameness not induced by experimental manipulation
  • Ulcerated tumors
  • Severe or ulcerative dermatitis. 

The following are signs for evaluating moribund condition in animals:

Signs of morbidity plus:

  • Impaired mobility (the inability to reach food and water)
  • Inability to remain upright
  • Hunched posture for more than 48 hours
  • Labored breathing and cyanosis (blue color to skin or mucous membranes)
  • Clinical dehydration and/or prolonged decreased food intake (more than 48 hours)
  • Muscle atrophy and signs of lethargy and lack of physical activity
  • Severe, rapid weight loss and emaciation (more than 20% of body weight)
  • Chronic diarrhea or constipation for more than 48 hours
  • Hematological or biochemical values that indicate organ failure
  • Prolonged frank bleeding from any orifice
  • Self-mutilation
  • Unconsciousness with no response to external stimuli

IACUC approved March 2010

Contact Info

Institutional Animal Care and Use Committee (IACUC)

Fax 541-737-9041

Office of Research Integrity
Research Office
Oregon State University
B308 Kerr Administration
Corvallis, Oregon 97331-2140
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