Policy on the Restraint of Research Animals

Institutional Animal Care & Use Committee
Aug 3, 2020 12:00 am

This policy defines “prolonged restraint” and is intended to ensure that: (a) the method of restraint is appropriate for the species of animal, (b) the period of restraint is the minimum required for experimental objectives, (c) the personnel performing the restraint have been appropriately trained, and (d) when prolonged physical restraint is necessary, the physical, physiological and psychological effects on the animal are minimized.

  • Background

    Access to an animal for the purposes of obtaining samples, administering medication or accomplishing study objectives is an important component of many studies using research animals. In most cases, this period of immobility is short term. On occasion, a prolonged period of restraint may be required to achieve the project objectives.

    The Guide notes that “Systems that do not limit an animal’s ability to make normal postural adjustments (e.g., subcutaneous implantation of osmotic minipumps in rodents, backpack-fitted infusion pumps in dogs and nonhuman primates, and free-stall housing for farm animals) should be used when compatible with protocol objectives.”1 Examples of such devices include nonhuman primate tethering systems that allow for all types of movement except 360-degree rotations parallel to the axis of the tether. Tethering that does not restrict normal posture is described separately from restraint within the animal care and use protocol.

    1 NRC (2010) The Guide to the Care and Use of Laboratory Animals. Washington D.C. National Academies Press
  • Applicability

    This policy is applicable to all vertebrate animal activities conducted under the auspices of the University, and applies to all campus locations, including Ann Arbor, Flint, and Dearborn.

  • Glossary Definitions

    Physical Restraint

    Physical restraint is defined by the Guide as “The use of manual or 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 manipulation.” Methods of restraint must be described in the animal use protocol and approved by the IACUC.

    Examples of physical restraint include:

    • Restraint chambers or devices
    • Unconventional tethering - tethering that suspends the rear legs above the cage floor or short tethering that actually restricts movement
    • Large animal stanchions

    Prolonged Restraint

    Prolonged restraint is defined as the physical restraint of an animal for a period exceeding 30 minutes.

  • Policy

    Prolonged restraint exceeding 30 minutes is considered unalleviated pain and/or distress (i.e., “Category E” for USDA covered species). Prolonged restraint must be scientifically justified in the protocol and should address the following:

    • 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.

    If severe behavioral changes, lesions or illness are observed as a result of the restraint, animals must be temporarily or permanently removed from restraint and ULAM veterinary staff should be consulted.

  • Compliance

    The provisions of this policy are under the direction and oversight of the U-M’s IACUC. The IACUC will, if necessary, suspend research or implement sanctions if policy infractions should occur.


For questions, additional detail, or to request changes to this policy, please contact the Office of the Assistant Vice President for Research, Director of the Animal Care & Use Office at acuoffice@umich.edu or (734) 763-8028.