IACUC Policy on Prolonged Physical Restraint of Animals

Background & Definitions

Physical restraint is the use of manual of mechanical means to limit some or all of an animal’s normal movement for the purpose of examination, collection of samples, drug administration, therapy or experimental manipulations.1  Professional judgment should be used to determine what is meant by “prolonged” restraint in terms of actual time; the length of time which could lead to distress in an animal will vary, depending on the species, type of restraint used, activities performed on the restrained animal, etc.  As a general rule, restraint that lasts longer than 15-30 minutes should be considered “prolonged restraint”.

The following circumstances are NOT considered prolonged restraint:

  • Holding an animal by hand or in a device (e.g., rodent restrainer, pig sling) for a few moments in order to collect blood or perform an injection
  • Use of sedation or anesthesia to limit animal movements during imaging procedures such as CT or MRI.
  • Walking a dog on a leash or transporting a cat or rabbit in a standard carrier


The use of prolonged restraint is potentially distressful and may only be used when it is essential for achieving research objectives.  It must be carefully described in the research protocol and reviewed and approved by the IACUC.

Important Guidelines1 for Restraint of Any Duration

  • Restraint devices should not be considered a normal method of housing, and must be justified in the animal use protocol (see Appendix D).
  • Restraint devices should not be used simply as a convenience in handling or managing animals.
  • Alternatives to physical restraint should be considered.
  • The period of restraint should be the minimum required to accomplish the research objectives.
  • Animals to be placed in restraint devices should be given training with positive reinforcement to adapt to the equipment and personnel.
  • Animals that fail to adapt should be removed from the study.
  • Provision should be made for observation of the animal at appropriate intervals, as determined by the IACUC.
  • Veterinary care must be provided if lesions or illnesses associated with restraint are observed.  The presence of lesions, illness, or severe behavioral change often necessitates the temporary or permanent removal of the animal from restraint.
  • The purpose of the restraint and its duration should be clearly explained to personnel involved with the study.