THE GREATEST COST IN BEEF PRODUCTION IS FEED. YET, BEEF CATTLE PRODUCERS ARE UNABLE TO SELECT ANIMALS FOR OPTIMAL FEED INTAKE, UNLIKE OTHER TRAITS. THE AMOUNT OF FEED THAT CATTLE CONSUME WHEN GIVEN UNLIMITED ACCESS IS NOT CONSISTENT, AND SCIENTISTS ARE UNABLE TO PREDICT FEED CONSUMPTION ACCURATELY. ONE OF THE MAIN REASONS WE CANNOT PREDICT FEED INTAKE IS THAT WE DO NOT FULLY UNDERSTAND THE MECHANISMS THAT REGULATE APPETITE IN CATTLE. THIS PROJECT HYPOTHESIZES THAT THE METABOLISM OF GLUCOSE BY TISSUES SUCH AS MUSCLE AND LIVER IS AN ESSENTIAL REGULATOR OF FEED INTAKE. THE OBJECTIVES OF THIS PROJECT ARE TO 1) DETERMINE THE ROLE OF GLUCOSE METABOLISM AND INSULIN SENSITIVITY IN REGULATING FEED INTAKE AND TO 2) DETERMINE THE ROLE OF METABOLISM AND MOLECULAR SIGNALING IN THE LIVER IN REGULATING FEED INTAKE. THE RESULTS OF THIS PROJECT WILL SHOW THAT CATTLE WITH GREATER FEED INTAKE HAVE A GREATER DEMAND FOR GLUCOSE AND ARE MORE SENSITIVE TO INSULIN. WE ALSO EXPECT TO FIND AN INCREASE IN MOLECULAR PATHWAYS IN THE LIVER THAT GENERATE GLUCOSE AND INCREASED EXPRESSION OF THE PROTEINS THAT RESPOND TO INSULIN IN MUSCLES. THE RESULTS OF THIS PROJECT WILL FILL A GAP IN THE KNOWLEDGE OF HOW GLUCOSE METABOLISM AND INSULIN ACTION REGULATE FEED INTAKE. THE RESULTS FROM THIS PROJECT ARE A CRITICAL STEP IN DEVELOPING A TOOL TO ALLOW PRODUCERS TO SELECT CATTLE WITH OPTIMAL FEED INTAKE. THE ABILITY TO GENETICALLY SELECT FOR OPTIMAL FEED INTAKE WILL IMPROVE THE ECONOMICS OF BEEF PRODUCTION BY REDUCING THE COST OF PRODUCTION. OPTIMIZING FEED INTAKE WILL ALSO MINIMIZE THE ENVIRONMENTAL IMPACT OF BEEF PRODUCTION BY REDUCING THE EXCRETION OF NUTRIENTS THAT ARE NOT USED BY THE CATTLE.