The University of Iowa



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New investigator guidance for monitoring and managing new weanling mice

Date: 2/12/19

In a continued effort to provide the best care possible for our rodent breeding colonies, OAR has evaluated practices for monitoring and managing new weanling mice.  A summary of the relevant changes to be implemented is listed below. 


  1. Cage Card specific for “Small Pups”:  In an effort to help labs and OAR staff in identifying new weanlings that need extra attention due to small size, we will institute a new cage identification card that is bright blue.  This card would be placed behind the “New Weanling” card anytime a small pup(s) is weaned. This also indicates that the person placing the card has added extra bedding to the cage and/or are using NapaNectar or other gel diet substitute to assist the pup(s) while they transition to standard water.


  1. Instructional Sheet: New Weanling Procedure for Labs
    1. This is a three page document that will help lab members understand steps OAR recommends to ensure that new weanlings have the resources available to grow and thrive. It includes photos and explanations for each step, in addition to a description and photograph on an important step sometimes overlooked: “priming the water valve”.  This is a method used to help teach new weanling mice where the source of water is located in their cage.


OAR veterinary staff will work with supervisors, caretakers, veterinary technicians and lab members to provide training on this new document over the next several weeks.


Please distribute this information and the attached guidance document amongst all individuals in your lab, particularly those with breeding management responsibility. 


The information contained in this email is also available through our website


As always, please send any questions to your facility veterinarian or