To investigate the regulatory role of follicle-stimulating hormone (FSH) on thecal androgen production and evaluate its impact on steroidogenic gene expression and oocyte viability in bovine follicles. Objective 1: To evaluate the effects of varying concentrations of FSH on proliferation rate and thecal androgen production in in vitro cultured bovine follicles. Hypothesis 1: FSH does not directly affect thecal androgen production in cultured bovine follicles. Objective 2: To examine the impact of FSH concentration on the transcriptomic profiles of steroidogenic-related genes in bovine follicles. Hypothesis 2: FSH concentration modulates the expression patterns of key steroidogenic genes involved in androgen and estrogen synthesis. Objective 3: To assess the effects of excessive FSH treatments on oocyte transcriptome integrity and viability. Hypothesis 3: Excessive FSH disrupts oocyte viability and alters the transcriptomic profile, potentially impairing subsequent follicular development. References: Armstrong, D.T., et al. (1979). Regulation of Follicular Estrogen Biosynthesis. Ben-Chetrit, A., et al. (1996). Ovarian Response to Recombinant Human FSH in LH-Depleted Women.

To elucidate the role of estradiol feedback on GnRH pulse generation in postpartum beef cows and its implications for the resumption of estrous cyclicity. Objective 1: To quantify changes in GnRH pulse frequency and amplitude in response to varying levels of estradiol during the postpartum period. Hypothesis 1: Estradiol levels positively regulate GnRH pulse frequency and amplitude, facilitating the resumption of estrous cyclicity postpartum. Objective 2: To investigate the relationship between estradiol levels and LH surge onset in postpartum cows. Hypothesis 2: A critical threshold of estradiol is required to trigger the preovulatory LH surge, with delayed estradiol rises contributing to anovulation in early postpartum cows. Objective 3: To assess the impact of estradiol supplementation on the timing of the first postpartum ovulation. Hypothesis 3: Estradiol supplementation during the early postpartum period will advance the timing of first ovulation by enhancing GnRH and LH surge dynamics. References: Stevenson, J.S., et al. (1999). Estradiol Regulation of Gonadotropin Secretion in Postpartum Beef Cows. Journal of Animal Science, 77(5), 1320–1326. Wiltbank, M.C., et al. (2018). Regulation of Estradiol and LH Surge in Cows. Theriogenology, 112, 6–15.

To investigate the regulatory relationship between kisspeptin and leptin as gatekeepers of puberty in beef heifers, evaluating their roles in hypothalamic pathways across developmental stages and production cycles. Objective 1: To elucidate the mechanisms by which leptin regulates Kiss1 expression in the hypothalamus. Hypothesis 1: Leptin acts as a Kiss1 regulator in the arcuate nucleus, influencing pulsatile GnRH frequency and subsequent reproductive processes. Objective 2: To determine if significant post-pubertal body weight fluctuations alter the neuroendocrine pathways involving NPY, POMC, and kisspeptin. Hypothesis 2: Significant weight fluctuations will impact neuroendocrine pathway function, potentially impairing reproductive efficiency in mature cows, but pathway structure will remain unaffected if fully developed prepuberty. Objective 3: To assess whether underdeveloped kisspeptin pathways can recover structurally and functionally with increased energy intake post-puberty. Hypothesis 3: Increased energy intake post-puberty can restore kisspeptin pathway efficiency, enhancing reproductive performance. References: Amstalden, M., et al. (2014). Hypothalamic Neuropeptides and Nutritional Programming of Puberty in Heifers. Journal of Animal Science, 92(8), 3211–3222. Cardoso, R.C., et al. (2018). Neuroendocrine Signaling Pathways and Nutritional Control of Puberty in Heifers. Animal Reproduction.

To evaluate the application of bovine anti-Müllerian hormone (AMH) testing in a large Mississippi beef cattle herd and determine its utility in improving reproductive performance and profitability. Objective 1: To determine the accuracy of a one-time AMH test in identifying fertility, longevity, and ovarian reserves in a large beef cattle herd. Hypothesis 1: The static nature of AMH levels throughout the estrous cycle will allow a single AMH test to reliably predict reproductive parameters. Objective 2: To assess the predictive value of AMH testing in untested heifers and compare AMH levels between beef and dairy cattle across regions, focusing on Mississippi herds. Hypothesis 2: AMH testing will predict reproductive longevity in heifers, with ideal AMH thresholds differing between Mississippi beef cattle and other breeds or regions. Objective 3: To perform a cost-benefit analysis of using AMH testing for heifer selection and culling decisions in beef cattle herds. Hypothesis 3: AMH testing will provide economic benefits by reducing costs associated with maintaining subfertile cows and improving herd reproductive efficiency. References: Umer, S., Zhao, S.J., et al. (2019). AMH: A Biomarker for Fertility in Domestic Animals. Genes, 10(12), 1009. Ansh Labs. Bovine AMH Testing.

To characterize the roles of leptin and insulin in reproductive hormone modulation and offspring viability in over-conditioned ruminants, addressing key gaps in knowledge relative to undernutrition studies. Objective 1: To evaluate offspring production and viability in over-conditioned female and male ruminants. Hypothesis 1: Over-conditioned ruminants will exhibit reduced offspring viability, with increased miscarriage rates in females and sperm abnormalities in males. Objective 2: To characterize leptin and insulin profiles and their effects on GnRH, LH, and downstream reproductive hormones. Hypothesis 2: Over-conditioning disrupts leptin and insulin regulation, inhibiting GnRH and LH surges, and reducing progesterone, estradiol, and testosterone fluctuations. Objective 3: To assess the effects of feed over-supplementation on leptin and insulin efficiency and subsequent GnRH/LH surges. Hypothesis 3: Feed over-supplementation leads to decreased leptin and insulin efficiency, disrupting kisspeptin signaling and reproductive hormone surges in over-conditioned ruminants. References: Harlow, et al. (2022). The Impact of Undernutrition on KNDy Neurons in Female Lambs. Nestor, et al. (2023). KNDy Neurons as the GnRH Pulse Generator in Ruminants. AIM 11: To investigate the potential of KNDy neurons as key modulators of puberty and GnRH activity in ruminants, addressing their role in neuroendocrine reproductive regulation. Objective 1: To evaluate the impact of neurokinin B absence on puberty onset. Hypothesis 1: Puberty will occur in the absence of neurokinin B, albeit at a delayed rate. Objective 2: To assess the functional consequences of removing specific KNDy neuron components. Hypothesis 2: Neurokinin B function will be significantly impaired in the absence of kisspeptins. Objective 3: To explore the potential of KNDy neurons as natural GnRH agonists or antagonists. Hypothesis 3: Isolated KNDy neurons can function as effective exogenous modulators of GnRH activity.

Which ONEof the following hormones prepares the fetal lungs for respiration?

From the outside in, the layers of the uterus consists of:

Which of the following is NOT one of the principal hormones of the Female Reproductive Cycle?

Which ONE of the following events indicates the start of human development?

The Adam’s apple is formed by the: