Environmental Enrichment Policy – Rabbits

Introduction

Boston University is committed to observing federal policies and regulations and AAALAC international standards for the humane care and use of animals.1 Humane considerations and current policies require that research animals, whenever possible, must have the opportunity to interact with conspecifics and to benefit from environmental enrichment (EE). This policy provides guidelines for handling and EE for rabbits.

Laboratory rabbits have partially adapted to captive life, but still reveal similarities to their wild counterparts demonstrating the fight-or-flight response. For that reason, the environment of the laboratory rabbit should, whenever possible, accommodate innate physiological and behavioral needs such as social contacts, resting, nest building, hiding, exploring, foraging, and gnawing.2.2 Rabbits historically are a prey species and are thus likely to show strong fear responses in unfamiliar situations when they cannot find shelter. Rabbits are timid and usually nonaggressive but will display defensive behavior including charging at the front of the cage, thumping, and biting, when frightened.

Rabbits require species-specific socialization and handling techniques. Teaching appropriate handling and carrying of rabbits to all involved in their care and use is especially important in order to avoid injury. The provision of frequent and gentle handling and daily routines have a calming effect on these animals and will reward laboratory animal staff as well as investigators with a more compliant research subject. Interaction with handlers, such as grooming, is a form of environmental enrichment. In addition, food enrichments plus manipulable objects should be provided.

Laboratory rabbits are used for many different types of experiments including orthopedics, cardiovascular studies, atherosclerosis, and ophthalmology. Less is published with respect to rabbits and the effect of EE on research data; however, one may assume that changes in the environment may have the same effect on experimental data as in other species. In general, these may include changes in various parameters such as immune factors and on stress hormones such as cortisol in addition to behavior. However, improved EE may also lower animal stress and normalize study results.2.2, 2.3

Purpose

A.   To define environmental enrichment for rabbits, including various ways to “facilitate the expression of species-typical behavior and promote psychological well-being through physical exercise, manipulative activities, or cognitive challenges”.1

B.   To define when exceptions are necessary to accommodate the research goals as approved by the IACUC.

Policy

A.   Rabbits may be individually housed or housed in compatible pairs or groups.2 Individual rabbit cages should be placed so as to allow visual, auditory, and olfactory contact with other rabbits.

B.   During review of the protocol, the principal investigator (PI) must consult with veterinary staff to discuss special circumstances that limit participation in the enrichment program. The veterinarian provides consult and recommendations to the PI as well as to the IACUC.

C.   In circumstances where an exemption from EE is required, the PI must include this in the IACUC protocol. The PI must specify the approximate duration of this exemption, specify if the exemption is for EE toys and/or food enrichment, and provide scientific justification for this exemption. All animals will be provided enrichment devices and/or food enrichment as determined by Boston University Animal Science Center (BU ASC) in all circumstances where no exemption has been approved by the IACUC.

Procedures

A. Food enrichments and treats should be scheduled into the regularly provided feeding regimen and given daily or several times a week. Treats providing roughage should be given unless contraindicated by the experimental protocol. Since rabbits are herbivores and have a large cecum, the regular feeding of items such as grass hay cubes, carrots, and other vegetables is beneficial to their digestion. In addition, since rabbit incisors as well as molars grow continuously, chewing allows teeth to wear down.

B. Other forms of enrichment:

Enrichment devices should be provided in the cage and exchanged and sanitized on a regular schedule.

  1. Suitable enrichment devices include large plastic balls which may be pushed around the cage, bells and bar bells, and chew sticks which may be either edible or made of wood. Hay can be provided for nest building and foraging.
  2. Novelty of enrichment through rotation or replacement of items should be a consideration; however, changing animals’ environment too frequently may be stressful.1
  3. Gentle handling and supervised exercise outside of the primary enclosure in a pen or designated safe area may be beneficial for the animal.

References

1.   The Guide for the Care and Use of Laboratory Animals. 2011. NRC ILAR. P. 52–55.  Environmental Enrichment.

2.   ILAR Journal 2005 Volume 46(2).

Enrichment Strategies for Laboratory Animals.

http://dels-old.nas.edu/ilar_n/ilarjournal/46_2/html/

2.1 Thomas L. Wolfle. Introduction. Environmental Enrichment.

http://dels-old.nas.edu/ilar_n/ilarjournal/46_2/pdfs/v4602wolfle.pdf

2.2 Vera Baumans: Environmental Enrichment for Laboratory Rodents and Rabbits: Requirements for Rodents, Rabbits, and Research.

http://dels-old.nas.edu/ilar_n/ilarjournal/46_2/pdfs/v4602baumans.pdf

2.3 Bayne, K.A. 2005. Potential for unintended consequences of environmental enrichment for laboratory animals and research results.

http://dels-old.nas.edu/ilar_n/ilarjournal/46_2/pdfs/v4602bayne.pdf

Websites
http://www.bio-serv.com/category/Rabbit_Enrichment_Devices.html
http://www.ottoenvironmental.com/

BU IACUC Approved September 2012, Revised January 2014