SOP 14.9 - Procedures for Caring for Mice Housed in Conventional Holding

1. Introduction and Definitions:

1.  Lights are on a 12:12 cycle, controlled by the Lutron lighting system
2. The conventional rooms have outward directional airflow, with a minimum of 15 ACH
3. Mice are housed within a Tecniplast GM500 rack or Tecniplast EM500 rack with cages having an outward directional air flow
4. A maximum of 5 mice per cage
5. Water is provided by the facility chlorinated automatic watering system and distributed to the individual cages using automatic water valves
6. Cages are changed a minimum of every 2 weeks
7. ATS and BSC’s are cleaned weekly
8. Although cages are not sterile, all husbandry and cage change procedures are performed in either an animal transfer station or biosafety cabinet to reduce personnel exposure to rodent allergens

Abbreviations: 

Air Changes per Hour ACH, Animal Transfer Station ATS, Biological Safety Cabinet BSC, Animal Care Services ACS, Principal Investigator PI

2. Daily Tasks:

1. Prior to entering the holding room, check the room temperature and humidity on the hallway monitor and record the information on the room sheet
2. Check the H₂O pressure reducing system, normal range should be between 3-7 psi. If outside normal range, notify the Associate Director, Animal Care Services
3. Turn on the ATS or BSC and let it sit for a minimum of 5 minutes prior to use
4. Ensure that you are familiar with any Special Requests that are posted in the room.
5. Clean all surfaces within the ATS or BSC with 0.5% accelerated hydrogen peroxide
6. Once the ATS or BSC has been running for 5 minutes and is disinfected, you may proceed with bringing in supplies
7. All cages are checked daily by observing the cage while it remains on the rack, including breeding cages
8. Cage side observations include the following:
   1. Observe the whole cage environment, including the food level, presence of a water spigot, bedding quality, signs of stool or feces, signs of nesting
   2. Are the mice in the nest? If yes, then mice are ok
   3. Are they outside the nest? If yes, take the opportunity to assess if they are active and performing normal behaviours, such as feeding or climbing or are they isolated and hunched, indicating a potential health concern?
   4. If you have a concern with any one of the factors above, then the cage is removed for further assessment
   5. Unhealthy mice present with clinical signs, for examples, hunched posture, squinted or closed eyes, splayed ears, piloerection, abnormal gait
       
9. Document any health concerns as per SOP 14.3 Clinical Health Reports - Rodent Records.
10. Record any new litters observed on the yellow breeding card located in the cage card holder
11. If pups have reached weaning age, place a “Wean” tag on the cage. If pups are beyond weaning age or a second litter is born, contact the cage card contact via email, requesting weaning
12. If a mortality is found, the following steps are taken:
    1. Mortalities are recorded on the electronic mortality/morbidity report and the mortality is reported via email to the Cage Card Contact
    2. All dead animals are removed from the cage, placed within a body bag, and the cage card is removed from the holder
    3. If the mouse has an identifier, make sure that the appropriate cage card is removed
    4. The date of death is added to the cage card and clipped to the ATS/BSC for the lab to retrieve
    5. The carcass is placed within the refrigerator when leaving the facility
        
13. There should be NO opening of the cage or exposure of the mice to room air. Boxes are only opened in the animal transfer station for husbandry procedures to minimize allergen exposure
14. Any wet, excessively soiled or orts filled cage is flagged for changing independent of the cage change schedule
15. Any flooded cage must be changed and recorded on the electronic cage flood log
16. Food is topped-up daily as necessary
17. Feed bins are changed when bringing in fresh food or at a minimum of once weekly
18. Feed bins are to be labeled with the Diet tag, which includes diet type, expiration date, mill date and lot number
19. Technical rooms associated with Conventional rooms must be checked daily, restocked and cleaned as necessary
20. Sweep floors and mop with 0.5% activated hydrogen peroxide
21. Garbage should be removed and placed in the waste collection bin in the anteroom to the facility

3. Bi-Weekly:

1. All mice are housed on the ventilated rack up to 5 mice per box and cages changed a minimum of every 2 weeks
2. When performing a cage change:
   1. Place new intake cage bottom in the ATS/BSC
   2. Place “dirty” cage within the ATS or BSC, remove the filter lid and place upside down
   3. Transfer the wire food hopper to the new cage bottom and top-up food as necessary
   4. Transfer mice to cage, checking sex of every mouse and making sure there are no obvious health problems
   5. Transfer the old nesting material to the new cage, only adding new nesting material if the old is too soiled or compromised to the point that the mice can’t build a new nest
   6. Transfer the igloo to the new cage, replacing the igloo if grossly contaminated
   7. Place the filter lid on the clean age and transfer the cage cards to the new cage
   8. Remove the dirty spigot from the rack and place in the dirty spigot box
   9. Place the new spigot on the rack, toggle the spigot and ensure that it is securely fixed
   10. Return the clean cage to the ventilated rack
        
3. Note that every other cage change (i.e. monthly) includes a wire food hopper and filter lid change out in addition to the cage bottom
4. Mouse cages with newborn litters are not to be changed until the litter is at least 3 days of age
5. Dirty cages are placed on a cart and transferred out of the room
6. At the end of the day, scan any racks that were changed for potential floods prior to leaving the room

4. Monthly:

1. Change wire food hoppers and cage filter lids
2. All surfaces should be cleaned with 0.5% activated hydrogen peroxide

5. Standard Enrichment:

1. All boxes have an igloo and nestlet pack