animals to laboratories
or water restriction
of expired materials
of Pain or Distress
in Fairview Patient Areas
Copyright 2000, University of Minnesota Board of Regents.
The University of Minnesota is an equal opportunity educator
Guidelines for the Prevention, Assessment and Relief of Pain
and Distress in Laboratory Animals
A key aspect of the animal welfare
regulations is that pain and distress be minimized whenever possible.
Therefore, it is necessary to design and perform experiments in such a
way as to prevent the animals from experiencing problems unless it is necessary
to achieve the goals of the study (i.e. category "c" studies).
It is not sufficient to merely
address these issues in a protocol. The animals themselves must be monitored,
and appropriate actions taken if pain or distress is observed. The problem
is that assessing pain and distress in animals is not a simple task. Animals
may not show signs of pain as readily as would a human being, and they
certainly can not communicate it in the same way. There is even great variability
among species in the way pain or distress is expressed. In general, animals
whose biological niche is that of a prey species (rodents, rabbits, nonhuman
primates, livestock) are less likely to alter their behavior in response
to pain than would a predatory animal, as doing so would make them a target
for predation. In addition, behaviors are often interpreted by humans in
the context of our understanding of what that behavior would mean for our
species rather than for the species being assessed.
Research Animal Resources
animal care and veterinary staff are
delegated by the IACUC to serve in the capacity of monitoring for signs
of pain and distress in laboratory animals. They are trained and experienced
in this area and are a good resource for monitoring the progress of studies.
However, investigators must also be aware of signs that an experimentally
induced or spontaneous disease is occurring in their animals. They may
have more contact with the animals than RAR, and ultimate responsibility
for the ethical use of animals lies with the investigator.
The following guidelines
are used by RAR, the IACUC and by regulatory agencies to determine if an
animal is experiencing pain or distress. A handout on assessing pain and distress may be downloaded HERE.
It is assumed that
for vertebrates, any procedures that would be expected to cause more than
slight or momentary pain or distress in a human being will cause similar
pain or distress in an animal, unless scientifically demonstrated otherwise. U.S. Govt Principle IV.
Distress is defined as a
maladaptive response to a stressor. It is recognized that some stress is
normal, but if animals react in such a way that their health is being compromised
(e.g. anorexia in response to induced disease or self-aggression in response
to psychological stress) this is considered distress.
Certain procedures are always
assumed to have the potential for causing pain or distress. These are the
basis for the numerous IACUC experimental guidelines that are intended
to prevent pain or distress. These include (associated guidelines for
these procedures are available by clicking on the highlighted links):
Animals subjected to these and
similar conditions are expected to receive appropriate monitoring
and any necessary supportive care,
analgesia, or anesthesia
to prevent pain or distress.
anesthesia and post-procedural care must
be performed in such a way as to prevent pain, infections and other complications
Repeated use of, large volumes
of, or intradermal injections of Freunds complete
of ascites-producing hybridomas for monoclonal
Prolonged (greater than 1 hour)
- Prolonged food
or water restriction
tail biopsy in animals over 3 weeks of age (tail snipping)
Electrical shock or other adverse
stimuli that are not immediately escapable
Paralysis or immobility in a
Organ failure resulting in clinical
Non-healing skin lesions
Whole body irradiation at high
Withdrawal of more than 10%
of an animal's blood volume
Studies that require the animal
to reach a moribund state or die spontaneously as the endpoint of the study.
The earliest endpoint
possible should be used to prevent pain or distress.
Despite these precautions,
pain or distress may occur as a consequence of a study or a spontaneous
of pain or distress may be based on many different criteria including:
Abnormal postures, hunched back,
muscle flaccidity or rigidity
Decreased food or water consumption
Decreased fecal or urine output
Weight loss (generally 20-25%
of baseline), failure to grow, or loss of body condition (cachexia)
Decrease or increase in body
Decrease or increase in pulse
or respiratory rate
Physical response to touch (withdrawal,
lameness, abnormal aggression, vocalizing, abdominal splinting, increase
in pulse or respiration)
Teeth grinding (seen in rabbits
and farm animals)
Vomiting or diarrhea
Objective criteria of organ
failure demonstrated by hematological or blood chemistry values, imaging,
biopsy, or gross dysfunction
of Pain or distress
The RAR veterinarian will consult
with the investigator to develop
a plan for treatment of animal health problems.
If an animal is experiencing
unrelieved pain or distress, it must be euthanized, unless an exception has been approved in the applicable animal care and use protocol by the IACUC..
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The information contained in this site is intended as
a reference for University of Minnesota investigators, and animal husbandry
and veterinary staff. Drug information and dosages are derived from a variety
of sources and do not necessarily guarantee safety or efficacy. Information
obtained through this site should not be relied upon as professional veterinary
advice. Any medications administered or procedures performed on animals
should only be performed by or under order of a qualified, licensed veterinarian.