Theses and Dissertations Collection

High protein diets support milk production in lactating dairy cows, however, high protein diets have been linked to lowered reproductive performance in cattle. The objective of the first study was to determine the effects of high urea and low pH on bovine endometrial (BEND) cells response to interferon-tau (IFNτ) with protein expression of Mx1 and ISG-15. In cattle, early embryonic loss may be due to the premature secretion of prostaglandin F2α (PGF2α) during the time of maternal recognition of pregnancy and luteolysis between days 14 and 16 after fertilization. Therefore, the objective of the second study was to determine the effect of aspirin administered during the time of maternal recognition of pregnancy on conception rates for lactating dairy cows that failed to conceive to a previous AI during the summer. Synchronization protocols aid in the synchrony of estrus and ovulation to maximize cattle fertility, however, many protocols often require multiple injections and animal handlings. The objective of the third study was to examine the effectiveness of one or two conventional PGF2α (12 hours apart), or one high-concentration PGF2α in a 5-day controlled internal drug release (CIDR)-Cosynch on progesterone (P4) profiles from the time of CIDR removal until AI and complete luteolysis (P4 > 0.5 ng/mL by AI) for suckling beef cows and lactating dairy cows.