91´ÎÔª

Physical or Prolonged Restraint of Laboratory Animals

Number: IACUC-POL-034 

Responsible Office: Office of Research and Creative Scholarship (ORCS) 

Applies to: All animal research and teaching protocols involving live vertebrate animals 

1. Purpose 

The 91´ÎÔª Institutional Animal Care and Use Committee (IACUC acknowledges that physical restraint of an awake, un-anesthetized animal may be necessary due to the scientific goals of certain studies. The IACUC has adopted the following policy to outline the minimally acceptable standards for physical restraint of laboratory animal species for experimental purposes. Personnel must attend any applicable training in animal care and use, occupational health and safety, equipment operation prior to performing activities of physical or prolonged restraint.   

2. Definitions 

Physical Restraint: The use of manual force or mechanical devices to restrict an animal’s movement for the purpose of facilitating examination, sample collection, drug administration, or experimental procedures. 

Prolonged Restraint: Restraint lasting longer than 15 minutes or repeated frequent restraint that may cause distress or interfere with normal behavior. 

Restraint Devices: Includes but is not limited to restraint chairs, slings, tubes, collars, vests, or restraining boxes.  

3. Background 

It is sometimes necessary to restrain animals for husbandry and research purposes, both to accomplish treatment or scientific objectives and to ensure the safety of the animal and the human handler. However, because prolonged restraint can be stressful and has the potential to cause harm to the restrained animal under certain circumstances, it is critical that considerable care and training is employed. Prolonged restraint should be utilized only when other means are not feasible and only following a determination by the IACUC that the objectives justify the procedures. Convenience alone is not deemed sufficient justification for prolonged restraint.   

The Guide provides the following definition for physical restraint: “Physical restraint is 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 manipulations.” Animals are restrained for brief periods, usually minutes, in many research applications. Restraint is assumed to involve immobilization and some limitation of normal postural adjustments.   

Prolonged restraint is defined as a physical restraint of a conscious animal lasting longer than 15 minutes (Guidelines for the Care and Use of Mammals. Neuroscience Research Council, 2003). Although the criteria for prolonged restraint vary according to species and type of restraint, it is generally considered to involve periods of more than 15 minutes.   

1. Restraint that does not require justification in an AUP:  
   • Brief (< 15 minutes) physical restraint that is part of normal animal-handling practices (e.g., moving mice from one cage to another).  
   • Brief physical restraint (<15 minutes) for procedures such as substance administration or sample collection (e.g., restraint of an animal to draw a blood sample).  
2. Restraint that does not require justification in an AUP but does require description: 
   • Brief mechanical restraint (< 15 minutes) of animals by personnel trained in the use of the device (e.g., rabbit or mouse restrainers to give injections or collect blood samples).   

4. To Consider When Restraint is Required  

• Alternatives to physical restraint should be considered. Systems that do not limit an animal’s ability to make normal postural adjustments (e.g., subcutaneous implantation of osmotic pumps in rodents or backpack-fitted instrumentation) should be used when compatible with protocol objectives.  
• 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 to adapt to the equipment and personnel.  
• Animals that fail to adapt to training should be removed from the study in consultation with the Attending Veterinarian.  

5. Requirements for Entering a Protocol with Prolonged Restraint Proposed 

• A description of the restraint device.  
• The duration the animal will be restrained.  
• A description of how the animal will be acclimated and trained prior to the procedure.  
• A description of how the animal will be observed during the procedure.  
• If the duration of prolonged restraint limits the ability of the animal to access food and water > 6 hours, the protocol must also include:  
  • A description of when food and water will be given  
  • How body weight will be monitored  

6. Training  

Any person using restraint procedures on an animal, even if for brief periods of time, must have received formal training and demonstrate proficiency (to someone who has already been trained) prior to carrying out these techniques unsupervised. If mechanical restraint devices are employed, they must be appropriate for the species, employ designs of known safety, and be in good working order. The device should be appropriate for the stated objectives (e.g. to minimize self-inflicted harm). Training must include practice in putting an animal into the device, as well as removing it safely.   

7. Animal Monitoring  

If the restrained animal can potentially hurt itself while restrained, or if restraint is employed to prevent possible interference with potentially dangerous catheters or other instrumentation, then monitoring must be continuous. Notations documenting this monitoring should be recorded each half hour, at a minimum. In general, continuous monitoring may be advisable if the period of restraint exceeds 4 hours. Even for shorter periods between 1-4 hours, monitoring at periodic intervals may be required to ensure the wellbeing of the animal. Indirect monitoring by camera may be utilized if the observer can respond to an emergency in a timely manner. A description of the monitoring procedures, including a statement about the frequency and duration of monitoring, must be included in the AUP.  

8. Restraint Monitoring  

Regardless of the length and frequency of restraint, close attention should always be given to the possibility of complications arising from restraint procedures. These problems initially could seem relatively minor, such as small abrasions or edema, but care must be given to preclude the possibility of exacerbation or infection. Food and water intake between periods of prolonged restraint should be monitored and body weights records should be maintained, especially in young or growing animals. The Attending Veterinarian or her/his designee have the authority to terminate the restraint procedures at any point should there be signs of complications that may compromise the animal’s wellbeing. Records of any complications must be maintained and be available to the IACUC upon request. The investigator must notify the AV to evaluate any clinical concerns and to determine if treatment is deemed necessary.   

9. References 

1. Guide for the Care and Use of Laboratory Animals, 8th Edition, National Research Council, 2011 Chapter 2: Animal Environment, Housing, and Management Chapter 3: Veterinary Care (p. 30): “Prolonged restraint should be avoided unless essential for achieving research objectives and must be approved by the IACUC.” 
2. Animal Welfare Act Regulations (9 CFR §2.31(d)(1)(iv)) Investigators must avoid or minimize discomfort, distress, and pain to animals and use appropriate sedatives, analgesics, or anesthetics. 
3. U.S. Government Principles for the Utilization and Care of Vertebrate Animals Used in Testing, Research, and Training Principle IV: "Proper use of animals, including the avoidance or minimization of discomfort, distress, and pain when consistent with sound scientific practices..." 
4. Public Health Service (PHS) Policy on Humane Care and Use of Laboratory Animals, 2015 
5. Requires compliance with the Guide and review by the IACUC of all proposed animal use procedures.  

10. Review, Approval and Version History 

Review and approval version history for this policy

Version	Date	Description of Changes	Approved By
1.0	August, 2018	Initial policy creation	IACUC Committee
2.0	June 4, 2025	Review and rewrite	Hicks