Precise phenotyping depends significantly on the quality of animal subjects. Stable housing and husbandry minimize the influence of exogenous factors that could distort phenotyping results. Additionally, mice submitted to the UMass MMPC share space with cohorts from microbiologically diverse sources. They, as well as mice housed in resident colonies, must be protected against potential cross-infection by adventitious agents. The Animal Care Core operates under the supervision of Dr. Jerald Silverman as the Core Director, who oversees the animal care facility of UMass Medical School. The Animal Care Core provides facilities and services relevant to these priorities under the following specific aims: (1) to provide stable, biocontainment housing, husbandry and health care for mice (2) to provide a dedicated room for housing (Podl-124 of LRB) and on-site phenotyping procedures, (3) to assess the microbiological profile of each cohort and provides the Center Director with interpretation and advice regarding the results, and (4) to provide to the users ofthe phenotyping service, at the discretion ofthe Center Director, results and advice on the health status of submitted mice. The goal of the Animal Care Core is to support the operation of UMass MMPC with issues pertinent to animal care and quality of phenotyping mice.