Date of this Version
Spuri Gomes, R. 2016. COWS WITH ANDROGEN EXCESS IN FOLLICULAR FLUID HAVE ALTERED REPRODUCTIVE CYCLES, SEX HORMONE BINDING GLOBULIN, METABOLISM AND GONADOTROPIN SECRETION. M.S. thesis, University of Nebraska.
Cow fertility is influenced by many factors. Two different studies were conducted with eleven different cows to better understand the mechanisms associated with infertility in cows with excess androgen in follicular fluid in their dominant follicle (High A4) compared to control counterparts (Low A4). The first study evaluated three different estrous cycles and determined that there was no difference in estrous cycle length. However, cows with High A4 ovulated without displaying estrus and/or displayed estrus without ovulating demonstrating that they had irregularities in their reproductive cycle. High A4 cows also had less circulating sex hormone binding globulin (SHBG), reduced circulating concentrations of LH and FSH, lower androstenedione (A4) and nonsterified fatty acids (NEFA) in plasma and altered rise and reduction in progesterone when compared to Low A4 cows. The objective of study 3 was to evaluate the response of these groups of cows to FSH and collect data at ovariectomy. High A4 cows had fewer granulosa cells per mL of follicular fluid and/or per follicles, different lipid composition in blood plasma during a non-stimulated cycle and after FSH stimulation in plasma and in follicular fluid when compared to Low A4 controls. In summary, these studies demonstrate that cows with androgen excess: (1) can ovulate without displaying estrus, and/or can display estrus but be anovulatory; (2) have different endocrine and metabolic profiles; (3) have impaired granulosa cell function potentially due to reduced number; and (4) have different lipid composition in blood plasma and follicular fluid. Thus, many of these alterations in endocrine and metabolic function may be contributing to reduced fertility in these High A4 cows.
Advisor: Andrea S. Cupp