The Unit for Laboratory Animal Medicine (ULAM) recently updated the Standard Operating Procedure (SOP) for Laboratory Assumption of the Feeding, Watering and/or Cage Changing of Rodents to provide additional clarification on when ULAM husbandry personnel will change rodent cages that are found to be wet/flooded.
This update does NOT require any action from laboratories who have been approved to provide their own care; however, a review of the revised SOP is strongly encouraged.
What Changed?
Previous language did not clearly define when a rodent cage is considered to be “flooded.” The SOP has been modified to articulate that a cage is flooded when ANY of the following occurs:
- Bedding is fully saturated with water, urine, or both
- Standing water is on the cage bottom
- Animals have no dry bedding to rest upon
Why is This Change Important?
Exposure to high levels of ammonia (i.e., NH3) and wet fur have been known to cause adverse health effects in laboratory rodents.
As such, no rodent can be left in a flooded cage for ANY period of time unless appropriate scientific justification has been provided by the Study Team and approval has been granted by the Institutional Animal Care & Use Committee.
What Did NOT Change?
ULAM staff will immediately transfer rodents to a dry cage if found in a cage with fully saturated bedding or standing water. Existing procedures for how laboratories will be notified of a potential animal health concern by ULAM husbandry personnel also remain unchanged.
These procedures are outlined in greater detail via existing MOUs Regarding Assumption of the Feeding, Watering and/or Cage Change of Rodents under ULAM Care by Investigative Personnel found in the SOP.
Questions?
Questions about this change or rodent husbandry procedures should be directed to the ULAM Husbandry Supervisor for your facility. 
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