IN THE DAIRY COW, THE TRANSITION FROM GESTATION TO LACTATION IS MARKED BY EXTREME PHYSIOLOGICAL AND NUTRITIONAL CHANGES THAT REQUIRE WHOLE BODY COORDINATED ADAPTATION. IF AN ANIMAL FAILS TO ADAPT TO THESE CHANGES, IT LEADS TO REDUCED PERFORMANCE AND INCREASED RISK OF DISEASE AND REMOVAL FROM THE HERD. AN APPROACH TO IMPROVING PRODUCTION AND HEALTH OUTCOMES IS TO ASSESS THE INDIVIDUAL ANIMAL'S REQUIREMENTS AND PROVIDE THE NUTRIENTS THAT ARE MOST REQUIRED FOR SUCCESS DURING THE TRANSITION PERIOD BASED ON THE INDIVIDUAL COW. THE OVERALL GOAL OF THIS 2-YEAR SEED PROJECT IS DETERMINE THE EFFECTS OF SUPPLEMENTING BRANCH CHAIN AMINO ACIDS (BCAA) TO DAIRY CATTLE PRIOR TO CALVING AND EVALUATING THE EFFECTS INTO LACTATION. SPECIFIC OBJECTIVES INCLUDE PROVIDING BCAA TO DAIRY CATTLE PRIOR TO CALVING AND ASSESSING MILK PRODUCTION, BODY COMPOSITION CHANGES, AND METABOLITE AND HORMONE CONCENTRATIONS. SECONDLY, PROTEIN ANALYSIS WILL BE CONDUCTED FROM MUSCLE SAMPLES COLLECTED FROM DAIRY CATTLE FEDWITH BCAA. LASTLY, ANIMALS WILL BE FOLLOWED FOR AN ENTIRE LACTATION TO OBSERVE WHEN BODY COMPOSITION CHANGES OCCUR THROUGHOUT THE LACTATION. THE PROPOSED RESEARCH ACTIVITIES WILL COMBINE NUTRITIONAL, PHYSIOLOGIC, AND OMICS WORK TO BETTER UNDERSTAND THE USE OF TISSUE TO MEET NUTRITIONAL REQUIREMENT DURING THE TRANSITION PERIOD OF DAIRY CATTLE. THE POTENTIAL IMPACT WILL BE TO PROVIDE INFORMATION ON PRECISION FEEDING OF DAIRY CATTLE BASED ON BODY COMPOSITION. THESE RESULTS MAY CHANGE THE WAY THAT WE GROUP, MANAGE AND FEED DAIRY CATTLE BASED ON THE REQUIREMENTS OF INDIVIDUAL DAIRY CATTLE.