APPROXIMATELY 30% OR BEEF CATTLE EACH YEAR FAIL TO OVULATE AN EGG (ANOVULATON) EACH REPRODUCTIVE CYCLE LEADING TO REDUCED REPRODUCTIVE PERFORMANCE. ANOVUALTION AND INFERTLITY CAN BE CAUSED BY ALTERED OVARIAN STEROID PRODUCTION AND INFLAMMATION. TO DETERMINE WHAT CAUSES INFERTILITY IN CATTLE, THREE EXPERIMENTS USING DIFFERENT MODELS (ANTRAL FOLLICLE COUNT, DIET, VACCINE) WILL BE USED TO DETERMINE THEIR ROLE ON INFLAMMATION AND SUBSEQUENT INFERTLITY. SOMATIC CELLS (THECA AND GRANULOSA) ARE INVOLVED WITH FOLLICULAR DEVELOPMENT AND OVULATION, BY INCREASING STEROID PRODUCTION AND SIGNALS FOR CELL GROWTH AND DEVELOPMENT. WHILE MUCH IS KNOWN ABOUT GRANULOSA CELL (CELLS SURROUNDING THE EGG) FUNCTION DURING NORMAL FOLLICULAR GROWTH, THERE IS A GAP IN KNOWLEDGE OF HOW ALTERED CONCENTRATIONS OF PRO-INFLAMMATORY MARKERS AFFECT FOLLICULAR PROGRESSION IN BEEF CATTLE. BASED ON PREVIOUS RESEARCH, OUR CENTRAL HYPOTHESIS IS THAT LOCALIZED INFLAMMATION (OVARY/UTERINE) DUE TO EXTERNAL FACTORS WILL ALTERGRANULOSA CELL NUMBER AND IMPAIR OOCYTE (EGG) QUALITY. WE WILL TEST THIS HYPOTHSIS BY: 1) INVESTIGATING THE ORIGIN OF CYTOKINE PRODUCTION AND THE LOCALIZED EFFECT ON GRANULSOA CELLS AND OOCYTES (EGGS). THE RESULTS FROM THIS STUDY WILL DETERMINE HOW ALTERED CYTOKINE PRODUCTION CONTRIBUTES TO GRANULOSA CELL STEROIDOGENESIS, PROLIFERATION AND OOCYTE (EGG) QUALITY, PROVIDING NEW INSIGHTS ON THE ROLE CYTOKINES IN GRANULOSA CELLS OF DOMINANT FOLLICLES.