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Policy#: 529-265

Title: ANIMAL USE GUIDANCE: Death as an End Point Studies in Rodents 1,2,3

Effective: 12/9/2004


Contemporary legal, regulatory and moral guidelines require that animal pain, distress and suffering be minimized in laboratory animals. Investigators should use their experience with the animal model to identify signs particular to their study that indicate that the rodent is dying and to administer euthanasia at that time. Otherwise, the general signs given below can be used. If death itself is absolutely required as the end point, the investigator may receive approval to conduct such studies by providing appropriate, scientific justification to the IACUC. Otherwise, investigators are expected to agree with the guidelines below and that they or the animal staff, following notification of the PI, will euthanize any animal found moribund. A further requirement of such studies is to minimize animal numbers within the statistical constraints of the project. Thus, in studies using death as an endpoint, investigators are encouraged to administer euthanasia prior to the actual death of an animal if the experimental validity will not be compromised.



As in all protocols, all animals will be monitored daily by the animal care staff. If signs of illness or disease are noted (see below), the cage will be tagged, and the date and abnormality described on the back of the card. The investigator and the Campus Veterinarian will be notified and the animal care staff will continue daily observations. If the abnormality is expected to lead to death of the animal but the animal is not yet moribund (see below), or if the animal has reached a known critical period with respect to impairment, the investigator must institute twice daily observations of the animal, early AM and late PM, including weekends and holidays, and euthanize the animal once it becomes moribund.


If a moribund animal is found by the animal care staff or the Campus Veterinarian, attempts will be made to alert the investigator or his staff, but if this is not possible or if the animal has not been euthanized within two hours, the animal will be euthanized by the animal care staff or the Campus Veterinarian.


Signs of Disease/Illness in Rodents

  • Ruffled fur - Slow, shallow and labored breathing
  • Hunched posture - lethargy - Rapid breathing
  • Poor appetite - Hypo- or hyperthermia
  • Diarrhea or constipation - Ulcerative dermatitis or infected tumors
  • Rapid weight loss


Signs of the Moribund Condition in Rodents That Require Euthanasia – Signs of disease/illness plus any of the following:

  • Impaired ambulation - unable to reach food and water easily
  • Rapid weight loss, >20% in one week
  • Poor appetite > 48 hours
  • Agonal breathing or cyanosis
  • Bleeding from any orifice
  • Severe diarrhea longer than three days
  • Inability to remain upright


1.        Hamm, Thomas E. - Proposed Institutional Animal Care and Use Committee Guidelines for Death as an End Point in Rodent Studies. Contemporary Topics 34: 69-71, 1995

2.        Olfert, Ernest D. - Defining an Acceptable Endpoint in Invasive Experiments. AWIC Newsletter 6:3-7,1995

3.        Tomasovic, Stephen P. - IACUC Evaluation of Experiments Requiring Death as an End Point: A Cancer Center's Recommendations. Lab Animal Jan/Feb. 31-34,1988


Originally approved: 12/17/96; Updated: 12/9/04