Home: Health

How to Tell if Your Pet is Ill or in Pain

Legal, regulatory, and moral guidelines require that animal pain, distress, and suffering be minimized in any experiment. For these reasons, investigators are encouraged to administer euthanasia in death endpoint experiments prior to the actual death of the animals if experimental validity will not be compromised. These objectives assume that investigators can differentiate between animals which are found morbid (i.e., affected with disease or illness) and those that are found moribund (i.e., in the state of dying).

Investigators must be able to judge and perform euthanasia on moribund rodents based on objective signs of dying, depending on experience with the animal model, professional judgment, and the experimental protocol. Some of the known signs of illness or dying which may be applied are listed below. Animals that are found in the moribund state should receive euthanasia.


Signs for Judging Morbidity (disease/illness) in Rodents

  • rapid respiration
  • respiration very slow, shallow, and laboured
  • rapid weight loss
  • ruffled fur (rough hair coat)
  • hunched posture
  • hypothermia or hyperthermia
  • ulcerative dermatitis or infected tumours
  • inappetence
  • diarrhoea or constipation

Signs for Judging the Moribund Condition (state of dying) in Rodents
Signs of morbidity plus:

  • impaired ambulation (unable to reach food or water easily)
  • evidence of muscle atrophy or other signs of emaciation (body weight is not always proportionate)
  • any obvious prolonged illness, including such signs as lethargy (drowsiness, aversion to activity, lack of physical or mental alertness), prolonged inappetence, bleeding, difficulty breathing, central nervous system disturbances, chronic diarrhoea or constipation
  • inability to remain upright

Signs of Pain in Animals

  • animal not alert
  • abnormal movement or postures
  • inappetence or dehydration
  • guarding reaction when likely areas of pain are palpated
  • vocalization when palpated or moved
  • self-mutilation
  • restlessness or lethargy
  • shock
 Where next?

Back to Health

To go to another section click on one of the links below:







General Information


The Mouse in Science




©2003-2006 Cait McKeown Home Email