AT THE TIME A DAIRY COW GIVES BIRTH, THERE ARE INTENSE METABOLIC CHANGESHAPPENING IN THE BODY. AFTER CALVING AND DURING THE FIRST WEEKS OF LACTATION (MILK PRODUCTION), THERE IS AN INCREASING ENERGY DEMAND FOR MILK PRODUCTION. HOWEVER, THE COW'S FEED CONSUMPTION IS REDUCED, THUS GENERATING AN ENERGY SHORTAGE. AS THE COW'S BODY RESPONDS TO THIS ENERGY DEFICIENCY, FAT TISSUES BREAKDOWN TO PROVIDEALTERNATIVE FUEL SOURCES USED BY DIFFERENT ORGANS. ONE MAJOR RESULT OF FAT BREAKDOWN IS THE FORMATION OF KETONE BODIES INTHE LIVER, WHICH ARE USED AS ALTERNATIVEENERGY SUPPLY MAJORLY BY MUSCLES AND THE UDDER. NOTABLY,IF PRODUCED IN EXCESS, KETONE BODIES CAN LEAD TO DISEASES, SUCH AS KETOSIS. COWS WITH KETOSIS HAVE INCREASED LEVELS OF KETONES IN THEIR BLOOD, URINE, AND MILK, ALONG WITH REDUCED MILK PRODUCTION, AND THEY ARE MORE LIKELY TO DEVELOP OTHER INFECTIOUS AND METABOLIC DISEASES DUE TO THEIR COMPROMISED BODY DEFENSES. KETOSIS CAN AFFECT UP TO 80% OF COWS IN EARLY LACTATION AND LEAD TO SIGNIFICANT ECONOMIC LOSSES IN THE DAIRY INDUSTRY. UNDERSTANDING HOW KETOSIS AFFECTS FAT TISSUE FUNCTION, INCLUDING ITS ABILITY TO BREAKDOWN DURING ENERGY SHORTAGES, IS AN IMPORTANT FIRST STEP TO FINDING NEW STRATEGIES TO PREVENT KETOSIS. WE BELIEVE FAT TISSUES CONTAIN UNIQUE TYPES OF CELLS WHICH RESPOND DIFFERENTLY TO ENERGY DEFICIENCY AND THEREFORE MAY BE INVOLVED IN THE DEVELOPMENT OF KETOSIS IN DAIRY COWS. IN THIS PROJECT, WE WILL STUDY HOW KETOSIS AFFECTS 1) THE GENETICS OF DISTINCT CELL TYPES IN FAT TISSUES AND 2) THE FUNCTION OF FAT CELL PROGENITORS (TYPE OF CELLS THAT ORIGINATE FAT CELLS) IN DAIRY COWS AFTER CALVING. WE EXPECT TO PINPOINT SPECIFIC CELL TYPES AFFECTED BY KETOSIS AND IDENTIFY THE MOLECULES INVOLVED IN THE DEFECTIVE FUNCTION OF FAT TISSUES DURING KETOSIS. FINDINGS FROM THIS PROJECT WILL PROVIDE A BETTER UNDERSTANDING OF HOW FAT TISSUES WORKIN DAIRY COWS AND HOW KETOSIS ALTERS THEIRFUNCTION. THE RESULTS OBTAINED FROM THE PROJECT WILL SERVE AS THE BASISFOR DEVELOPING NEWNUTRITIONAL AND THERAPEUTIC INTERVENTIONSTO PREVENT METABOLIC DISEASES IN DAIRY COWS AND REDUCE COSTS DUE TO DECREASED ANIMAL HEALTH AND WELFARE.