The Animal Core provides extensive scientific support services, including importation/exportation, colony management, customized mouse models, rederivation and creation of genetically-modified mutant mice (e.g. CRISPR), and re-animation of a variety of models (e.g., KOMP) cryopreserved and available from the Mutant Mouse Resource and Research Center (MMRRC) Consortium.   The Core can also produce male and female cohorts of mice for in vivo phenotyping under a variety of vivarium environments, including Specific Pathogen Free (SPF), Gnotobiotic, and ABSL3 conditions.   The Core operates a Microsurgery Suite, with two expert microsurgeons, for development of surgically-manipulated mouse models, such as bariatric surgical models, e.g. Vertical Sleeve Gastrectomy (VSG) and Roux en Y Gastric Bypass (RYGB), as well as cannulation telemetry and osmotic pump implants, in addition to providing microsurgery training services for investigators and clinicians. In addition to testing, manipulation, and sampling, investigator can have these surgically-manipulated models as well as any genetically-engineered mouse lines shipped from our approved vendor barrier vivarium directly into the recipient institution’s vivarium. The Core provides ancillary services and procedures, including gut microbiome studies, blood and tissue sampling, glucose and insulin tolerance tests, and more. The Core also provides anatomic and clinical pathology services, including gross necropsy with histology, clinical chemistry, and hematology. Testing can be customized to include specific organ histologic examination, grading and photo documentation. The Core is led by Kristin Grimsrud DVM, PhD, who oversees the mouse management technicians. Denise M. Imai-Leonard, DVM, PhD, DACVP, and Director of the UC Davis Comparative Pathology Laboratory, provides Core users with comprehensive pathology services.