Jennifer R. Wood
Date of this Version
Bochantin, KA; Evaluating the effects of pro-inflammatory cytokines on ovarian somatic cell function and immune response in cattle; Master's Thesis, University of Nebraska-Lincoln; May, 2020
Reproductive performance in cattle is influenced by many factors, including genetics, environment, nutrition, and overall physiological health. The immune system plays a critical role in this as well. Chronic, low-grade inflammation may influence fertility in cattle. In this study, we identify a population of cows within the UNL physiology herd that have increased circulating concentrations of TNFa (High-TNFa), a pro-inflammatory cytokine. Cow classified as High TNFa also had elevated concentrations of pro-inflammatory cytokines compared to Control cows, indicating a systemic inflammatory response. The objective of the study was to evaluate how systemic inflammation may contribute to metabolic disorders, such as insulin resistance, and ovarian function in cattle. While there were no differences in glucose and insulin levels between Control and High TNFa cows, concentrations of androstenedione (A4) were significantly decreased in the follicular fluid of small and large follicles. Additionally, mature cows classified as High TNFa tended to have delayed attainment of puberty and decreased reproductive performance. Cows in this study that were not cycling at the time of first breeding had increased insulin:glucose ratio, compared to cows that cycled, suggesting decreased insulin sensitivity. Together, these results indicate that cows with delayed attainment of puberty may be more susceptible to environment factors that may contribute to chronic, low-grade inflammation later in life. Collectively, these factors could be contributing to altered ovarian androgen synthesis and decreased fertility in cattle. Future studies will focus on determining the effect of systemic inflammation on ovarian somatic cell immune and steroidogenic function.
Advisor: Jennifer R. Wood