PSI-7 Differing planes of nutrition affecting the cytokines of bovine seminal plasma in beef cattle

Abstract

Abstract Bull fertility is highly influential to profits of cow-calf production; however, bulls often experience various planes of nutrition throughout the year. These changes may influence the composition of the ejaculate and their ability to get females pregnant. We hypothesized that differing nutritional planes would affect the cytokines concentration in the seminal plasma of bulls. Mature angus bulls (n = 12) were individually housed and randomly assigned to one of two treatments: 1) over-fed (n = 6) or 2) restricted (n = 6). Bulls were fed the same ration (35% ground hay, 35% cracked corn, 20% distillers’ grain and 10% soybean meal) at differing volumes to achieve desired nutritional planes. Body weight and BCS were taken every two weeks to monitor nutritional planes. Blood and ejaculate were collected once a month to determine cytokine profiles within seminal plasma. Statistical analyses were conducted with GLIMMIX procedure of SAS with bull within treatment as a random effect and time as a repeated measure to determine if nutrition level, time and the interaction influenced seminal plasma cytokine concentration. There were no significant time or treatment×time interactions for any cytokine concentrations. Interferon-γ tended to be increased (P < 0.10) in restricted bulls (3.21±0.95 pg/mL) compared with over-fed bulls (0.64±0.95 pg/mL). The concentrations of IL-8 also tended to be increased (P < 0.10) in restricted (318.89±66.42 pg/mL) compared with over-fed bulls (158.02±66.42 pg/mL). Interleukin-1β in over-fed bulls (24.77±17.51 pg/mL) tended to be decreased (P < 0.10) compared with restricted bulls (65.8±17.51 pg/mL). Interleukin-10 tended to be greater (P < 0.10) in restricted (17.95±2.29 pg/mL) than in the over-fed bulls (12.41±2.29 pg/mL). The concentration of VEGF-A was greater (P < 0.05) in restricted bulls (3,551.28±224.49 pg/mL) than over-fed bulls (2,715.72±224.49 pg/mL). In conclusion, cytokine concentrations were elevated by restricted nutritional levels which could impact the ability of the ejaculate to stimulate uterine gene expression and establish pregnancy.