Rat Husbandry and Care

Last updated: May 3, 2017


I. Purpose

This Standard Operating Procedure (SOP) outlines the animal care requirements associated with the daily husbandry of rats to ensure consistent and uniform care. This procedure applies to all personnel involved in the care of rats housed in static micro-isolator caging in the Laboratory Animal Resources (LAR) facility on the campus of the University of Montana.

II.   Policy
It is a LAR policy to meet or exceed all federal, state, and local regulations and guidelines and to comply with all institutional policies and procedures as they apply to the use of animals in research. LAR personnel must pass on-line animal training modules and attend applicable training in animal care and use, occupational health and safety, and equipment operation prior to performing activities outlined in this SOP. Animal housing rooms should be entered using appropriate personal protective gear for the species and disease or hazard containment level.

III. Veterinary Care Procedures

  • Each morning a Laboratory Animal Technician will observe all animals in each cage for signs of illness, injury or death. Signs of illness may include, but are not limited to, rough hair coat, hunched posture and/or reluctance to move, alopecia, ocular and/or nasal discharge, prolapsed rectum, abnormal stool or urine and listlessness.
  • If a health problem is detected, place a yellow Vet Check card on the cage and report the problem to the veterinary technician.
    • If there are no health problems to report, record date, time, number of births and deaths, and your initials on the Room Check Sheet.
  • If a rat is found dead, record the date on the cage card and notify the PI or his/her lab designee. Remove the carcass from the cage, put it in a marked bag and place in the carcass freezer unless there have been other instructions from the PI.
    • If an animal is found dead during the quarantine period, contact the AV immediately.
  • Observe breeding cages for new litters. Record the date of birth and the number of pups born on the cage card. Notify the PI or his/her lab designee and record information on the room check sheet.
    • For weaning purposes, use the date of birth as day 0.
    • Place a sticky note on the cage lid denoting the weaning date which is 21 days after the birth of the litter.
    • If a litter of weanlings is observed past 21 days of parturition, follow the SOP for weaning and charge tech fees to investigator.
IV. Husbandry
   Husbandry: daily
  • Feed rats Harlan rodent diet 2020X, unless otherwise instructed.
  • Add fresh food to feeders that are 1/4 full or less. Feed that appears to be wet, moldy, or contaminated with non-food materials, etc., should be discarded immediately.
  • Refill water bottles that are less than half full from carboy located in the room.
   Husbandry: weekly
  • Use the transfer station to change bedding twice a week on Mondays and Thursdays for rats, more often if necessary.
  • A bedding change for rats includes providing a clean box bottom with bedding and enrichment (autoclaved Kimwipes, wooden blocks and cereal treats).  Refill all water bottles on bedding change days. 
  • Spray racks with Rescue RTU at the time of cage changing and wipe down with towels as you clean the boxes.
  • Bedding changes for rats will be done on alternate weeks from full cage changes (see next section).
   Husbandry: bimonthly
  • A full cage change [box bottoms, wire bar lids (hoppers), micro-isolator filter tops, cage card holders, water bottles and sipper tubes] must be done at least once every two weeks on Thursdays.
  • Use transfer station to open and change only one cage at a time and transfer the old cage card to the new cage card holder.
  • Add a new Kimwipe and cereal at every full cage change.  Reuse wooden block until a new block is needed.
  • Remove soiled water bottle and replace with a clean full water bottle. Position the bottle to ensure that animals have access to the sipper tube and that no leakage is occurring.
  • Spray racks with Rescue RTU at the time of cage changing and wipe down with towels as you clean the boxes.
  • If the old feed from the dirty box hopper is clean and dry, you may reuse that feed (place in clean hopper) for the same mice during a full cage change. Add new feed as needed. Label all feed barrels with feed type, milling date, and sanitation date of the container. Food expires 6 months from the milling date and should be discarded at that time.
  • Return all cages to their original location on the rack after full cage change. Full cage changing should be performed in an orderly pattern, until all shelves on the rack have been completed.
  • Wipe down the cage changing table with disinfectant solution between rodent strains or between racks (which ever comes first).
  • Spray gloves with disinfectant solution [Rescue RTU] after each box change. Gloves should be changed between rodent strains.
  • Cover stacks of dirty cages with a filter lid and transport to the dirty side of cage washer for processing.
  • To clean sipper tubes use a vinegar soak if excess calcium persists. Rinse tubes and wash thoroughly.

  Husbandry: Wet Box

  • Remove rodents from wet box and dry off with KimWipe or other absorbable material.
  • Replace wet housing box and related items (filter top, hopper, clean water bottle, lixit and cage card holder) with clean housing set up.
  • Shred up a new nestlet and place into a corner with a new TP roll.
  • Clear the bedding from one end of the box and place a heating pad underneath on medium heat.
  • Add a small amount of moistened rodent chow on floor of cage (2-3 food pellets).
  • Re-check mice for next several hours until no signs of distress are present.
  • Unplug the heat pad and leave a sticky note on the box for further checking.
  • Document cage number, mouse ID on daily log sheet. 

V. Sanitation

  • Sweep floors in animal housing rooms daily Monday thru Friday and as needed on the weekends. Always mop floors in animal housing rooms daily after sweeping and on weekends as needed.
    • Prepare a fresh solution of Rescue concentrate in mop bucket immediately prior to mopping floor each day. 
      • Empty the old water in bucket into sink.
      • Use a 1:64 dilution of Rescue concentrate in 8 liters of water.
    • Place dry mop into fresh water solution and thoroughly wet mop.  Squeeze excess water from mop and mop entire room floor.
    • Rinse mop in bucket and squeeze excess water from mop.  Drape squeezed mop over mop press allowing mop to hang over bucket to dry completely.
    • Do not allow mop to sit inside mop press or in the bucket of water.
  • Empty trash containers daily. Replace trash bag with a new one.
  • Empty and wipe down room supply carts, where available, as needed, but not less than once monthly with Rescue RTU solution.
  • Clean and disinfect feed and bedding barrels with Rescue RTU after removing contents.  Disinfect at least once monthly
  • Feed and bedding container information cards are to be kept up to date.
    • Bedding container information
      • type of bedding
      • vendor
      • sanitation/disinfection date
    • Feed container information
      • type of feed
      • vendor
      • milling date
      • sanitation/disinfection date
  • Shelf racks are to be free of dust and debris at all times.
    • Weekly: disinfect the racks with Rescue RTU solution during bedding and full cage changes.
    • If extra shelf racks are available, racks are to be rotated out of the room and sanitized in the rack washer at least once every 3 months.