Environmental Enrichment for Animals SOP

Unit for Laboratory Animal Medicine
May 17, 2024 12:00 am

This document outlines the use and approval of environmental enrichment for all vertebrate animals.

  • Responsibility

    1. Behavioral Welfare Group (BWG)
    2. ULAM Trainer 
    3. ULAM Husbandry Personnel
  • Glossary Definitions

    Animal Enrichment Database (AED)

    The central database used to track the approval status and details of all enrichment methods and items used.

    Behavioral Welfare Group (BWG)

    A group of designated individuals, including a faculty veterinarian, which works as a single point of contact for behavior, welfare, enrichment and social housing related issues.

    Nesting Material

    Commercially available shredded paper (e.g. Crinkle nest, Envirodri or Enviropaks), nestlets, Alpha Dry or Carefresh bedding.

    Principal Investigator (PI)

    The researcher who has received protocol approval to conduct the study.

    Social Species

    Species regarded as highly interactive with members of their same species and whose psychological well-being is associated with social interactions. Examples of social species include, but are not limited to, canines, primates, rodents, rabbits, sheep, and swine.

    Special Treatment or Procedure (SToP) Form

    A form that indicates special procedure differing from standard operating procedure (SOP). These are typically placed on the inside of the animal room door. See Request for Special Treatment or Procedure (SToP) Form for more information.

  • Procedures

    1. Animals That Receive Enrichment

    1. Provide vertebrate animals enrichment regardless of social housing status unless a SToP Form is in place and it is justified in the AUP or for animal health reasons.
    2. Provide single housed animals more than one enrichment item.
      1. Ensure additional enrichment item(s) are different from the first enrichment item, where possible. 
      2. Add the additional enrichment at the first cage change from when the animal is noted to be single housed.
    3. Limit the number of items given (i.e., offer only 2 items to a single housed animal; offer 1-2 items per animal for a pair of larger animals) to encourage novelty of environmental enrichment items and to alleviate resources.
      1. Consult the BWG and the area faculty veterinarian to develop enrichment plans for large groups (>5 animals) of socially housed animals.
        1. Group housed sheep at the Sheep Research Farm do not necessarily require one item per animal as long as no negative interactions involving enrichment are observed.
    4. Enrichment suggestions for various species include:
      1. Mice, gerbils, hamsters, voles:
        1. Provide at least one form of nesting material, where possible.
        2. Provide voles a wooden chew toy at all times, where possible.
        3. An additional enrichment item can be a different form of nesting material, e.g., if the mouse currently has a nestlet; envirodry or an enviropak could be added.
        4. Refer to the AED for other secondary enrichment options.
      2. Rats and guinea pigs:
        1. Provide at least one hiding opportunity in the form of a shelter or shelf, where possible.
        2. An additional form of enrichment item can be a different form of hiding opportunity, e.g., if the rat has a shelf, a tube or shelter could be added.
        3. Refer to the AED for other secondary enrichment options.
        4. Gnawing opportunities should be prioritized over nesting material.
          1. Nesting material can be provided as a secondary enrichment item to rats, however nesting material is generally not considered as valuable for rats as it is for mice.
        5. Rotate the additional enrichment item(s) for novelty on subsequent cage changes, where possible.
      3. Large animal species such as rabbits, pigs, sheep, cows, cats and ferrets:
        1. Rotate the enrichment items for novelty and to prevent boredom on subsequent cage changes, where possible.
          1. See Appendix A for a hanging quick guide on enrichment strategies involving animals single housed alone or with conspecifics in a room.
      4. Dogs and NHP: See the species-specific SOPs in the Related Documents section.
      5. Zebrafish:
        1. Brine shrimp are the most common form of enrichment given to zebrafish.
        2. Prioritize visual access to other fish (i.e. fish in a neighboring tank), which can qualify as the secondary enrichment option for single housed zebrafish.
        3. Provide additional approved enrichment items for zebrafish without visual access to other fish.
          1. Refer to the AED for other secondary enrichment options. 
      6. Chickens:
        1. Provide an adequate amount of perching space to ensure all chickens can roost comfortably. 
      7. Aquatic frogs:
        1. X. laevis spp
          1. Provide:
            1. A plastic plant, or
            2. PVC tube of appropriate size.
        2. Hymenochirus spp
          1. Provide:
            1. Gravel or a photo of gravel under the tank
            2. Plastic plant(s)
            3. Plastic mouse huts/igloos/tents

    2. Providing Enrichment

    1. Provide enrichment to vertebrate animals unless a SToP Form is in place stating otherwise.
    2. Review enrichment options as described in the AED and select an appropriate enrichment item based on species and individual animal size.
    3. Position single housed large animals where each animal can visually see the other, whenever possible.
      1. Report to the faculty veterinarian and social housing coordinator if adverse social behaviors or signs of distress are noted with this housing method.
    4. Position a mirror for single housed large animas to visualize a reflection to mimic the presence of a conspecific when individually housed in a room.
      1. Mirror usage for animals does not take the place of providing other approved environmental enrichment items, except in zebrafish as stated in Procedures section 1.c.v.2.
    5. Where applicable:
      1. Ensure smaller items do not go down drains.
      2. If item can be pushed out through the cage bars, do not use as sole enrichment item.
      3. Remove any item that is broken or excessively worn; recover all broken pieces.
      4. If hanging items are no longer hanging, locate and remove clip.
      5. Watch for animals ingesting pieces of items.
      6. Ensure chains used to hang items are no longer than three chain links (plus fasteners).
        1. Appropriately cover chains that are longer than three chain links.
        2. Exception: tree shrews may have uncovered chains or zip ties at the discretion of the faculty veterinarian.
    6. Change enrichment items at regular intervals or as required per AED; and rotate items to maintain novelty of the items and prevent boredom when possible.
      1. Replace, sanitize, or transfer enrichment at cage change as appropriate for all species. The type of enrichment does not need to be recorded on Room Sheet (e.g. Animal Room Log Sheet) except for NHPs.
        1. Record NHP enrichment on the Nonhuman Primate Enrichment and Husbandry Log. See Non-Human Primate Husbandry SOP, Appendix B.

    3. Approval of New Enrichment Items

    1. The Behavioral Welfare Group (BWG) approves all enrichment items not found in the AED prior to implementation.
      1. Submit new enrichment ideas or examples to the Behavioral Welfare Group: Request for Approval of New Enrichment Item. Provide the following information:
        1. Costs for each item (purchase price or labor to construct).
        2. How labor intensive the enrichment is projected to be.
        3. Novelty of enrichment item.
        4. Proposed schedule of applying and rotating enrichment.
        5. Item disinfection requirements.
      2. The BWG evaluates each item and enters all relevant information into the AED whether approved or denied for use. Include the following information in the AED:
        1. Approved items:
          1. Item name 
          2. Item description
          3. Approved species use
          4. Approved disinfection procedures (if applicable)
        2. Denied items:
          1. Name
          2. Reason for denial
      3. The BWG can approve items on a trial basis with PI consent.

    4. Training

    1. Trainers or area supervisors ensure training of all relevant enrichment items in the area for husbandry technicians prior to employing use of any items.
    2. Training can be done by providing:
      1. Detailed descriptions of item applications via the AED.
      2. Demonstrations of application for any items that:
        1. Involve safety concerns for the humans or animals (i.e. NHP enrichment).
        2. Are not routinely used.
        3. Involve direct handling of the animals (i.e. hand walking canines).

    5. Cleaning / Sanitizing Enrichment Items

    1. Clean, disinfect, sanitize or discard items in accordance with the information in the AED.
    2. Transfer certified wood enrichment items with animals at cage change if not soiled, splintered or brittle.
      1. Discard soiled, splintered or brittle wood enrichment and replace as needed.
  • Appendix A: Large Animal Standard Enrichment Room Poster