DAIRY COWS REQUIRE GLUCOSE FOR MILK SYNTHESIS AND MANY OTHER PHYSIOLOGICAL PROCESSES, INCLUDING OPTIMAL IMMUNE FUNCTION. IN HUMANS AND RODENTS, GLUCOSE HOMEOSTASIS IS REGULATED THROUGH CIRCADIAN RHYTHMS IN HORMONE SIGNALING AND GENE EXPRESSION. HOWEVER, THE ROLE OF CIRCADIAN RHYTHMS IN GLUCOSE METABOLISM OF THE DAIRY COW IS UNKNOWN. THIS STUDY WILL DETERMINE HOW THE KINETICS OF GLUCOSE UPTAKE, INSULIN RELEASE, AND LIPID RELEASE CHANGE ACROSS THE DAY. FURTHERMORE, THIS STUDY WILL EXAMINE IF CIRCADIAN RHYTHMS INFLUENCE THE RELEASE OF GUT-PRODUCED INCRETINS GLUCAGON-LIKE PEPTIDE 1 (GLP-1), AND GLUCOSE INSULINOTROPIC PEPTIDE (GIP), AND THEIR EFFECT ON INSULIN SECRETION.