Prenatal exposure to excess androgens, testosterone in particular, has clear effects on potential ram fertility. Utilizing breeding soundness examinations in male sheep will assess the ram's potential ability to impregnate a certain number of healthy females during a defined breeding season. Identifying rams that have high breeding potential can provide...
Follicle stimulating hormone (FSH) plays a key role in the ewe’s estrous cycle but understanding its continued importance during pregnancy is not well understood. Researchers have proposed a model theorizing that a cascade of hormones is responsible for pregnancy maintenance. Weems et al. proposed a model for placental progesterone production;...
Recently, an interest in supplementation of vitamin D to improve aspects of health, especially in human fertility, has emerged. However, supplementation of Vitamin D above the minimum required levels to prevent deficiency has yet to be explored in cattle despite evidence for vitamin D receptors in reproductive tissues. The objective...
Two studies evaluated the mineral status of supplemented beef cattle over two different methods of supplementation. The objective of study 1 was to evaluate the mineral status at weaning and subsequent post-weaning performance of calves supplemented prior to weaning, with limited-fed supplements fortified with trace minerals (Cu, Se, and Zn)...
Mastitis is a major endemic disease in dairy cows resulting in significant economic losses for the dairy industry. The peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor that is able to bind and be activated by natural (e.g., fatty acids) and synthetic (e.g. thiazolidinedione) compounds. PPARγ plays important roles...
The objective of the present research was to determine, by use of the progesterone receptor antagonist RU-486, whether progesterone by autocrine/paracrine action suppresses phosphatidylinositol hydrolysis, and thus, the production of prostaglandin F2a during the midluteal phase of the estrous cycle in ewes. Two experiments were performed. Experiment 1 consisted of...
The majority of the world's breeding population of northern fur seals (Callorhinus ursinus) is found on the Pribilof Islands (St. Paul and St. George) in the Bering Sea, Alaska. Pup production on these islands experienced an irregular but overall decline since the early 1970's. Between 1998 and 2010, pup production...
The following experiment presented herein compared growth, physical activity, stress-related responses, and puberty attainment in heifers reared on high- (HIDENS) or low-stocking densities (LOWDENS). Sixty Angus x Hereford heifers were ranked by age and BW (210 ± 2 d and 220 ± 2 kg, respectively) on d 0, and assigned...
Growing concerns over the rise of anthelmintic resistant populations of gastrointestinal nematodes (GINs) have led producers to look for alternative means of treatment. These sentiments have been echoed by organic producers, who are restricted from the use of synthetically derived anthelmintics in the US. Chicory has emerged as a potential...
T cells are one of the key cells in the immune system. Although they are not the first line of defense against a pathogen, their functions can greatly enhance the phagocytosis and destruction of pathogens as well as the development of antibody responses. Furthermore, even when responding T cells have...