The Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC) and the Public Health Service require that institutions base their animal care and use programs on the “Guide for the Care and Use of Laboratory Animals” (the Guide). The NYU Institutional Animal Care and Use Committee (IACUC) must comply with the national standards and recommendations contained within the Guide when establishing mouse cage populations.

DLAR utilizes “shoe-box” cages for housing mice which provide 63.0 in2 (ventilated cages) or 68.2 in2 (standard static cages) of floor space. The IACUC and the NYU Division of Laboratory Animal Resources (DLAR) have established the following standards for mouse housing:

1. Five adults mice (< 25 g); or

2. One adult pair with litter. Pups must be weaned at 21 days of age; or

3. One adult female and litter of pups when pups are weaned between 22-28 days of age. This weaning date is for select transgenic/knock-out strains requiring additional suckling time. No adult males and no post-partum estrus breeding are allowed in these cages unless approved by the IACUC; or

4. Two adult females can be combined before parturition with 1-2 litters. No more than 10 pups of approximately the same age can be housed in this cage. Pups must be weaned at 21 days of age and NO ADULT MALES are allowed in these cages unless approved by the IACUC.

Excluding the last alternatives, which are generally reserved for transgenic/knock-out strains or some inbred strains (i.e. C57/BL6, 129SV, FVB/N); multiple litters are not permitted in the “shoe-box” mouse cages. Harem breeding is discouraged, however, individual situations may be accommodated if justified and approved by the IACUC.

Cages identified as exceeding the maximum limits, will be identified by DLAR and must be separated. The investigator is given seven days to separate or decrease the cage population. If the population is not corrected within the seven days, DLAR staff will separate the cages and the investigator will be charged a separation fee. A fee will also be charged for “notification of overcrowding” labels that are removed from the cages by the investigator and cages not separated. Cages determined to be extremely overcrowded (i.e. multiple litters of different ages) by the DLAR staff will be separated immediately and the investigator will be charged accordingly. Charges for all services are posted on the website.

Effective August 11, 2004