PSI-14 - Effects of Estrus Expression on the Microbial Community Composition of the Uterus in Beef Cows on Day 15 of the Estrous Cycle

Abstract: The objective of this study was to evaluate the effects of estrus expression on uterine microbiota composition of cows on day 15 of the estrous cycle. Non-pregnant Bos taurus beef cows (n = 23) were exposed to a pre-synchronization step followed by the 7-d CO-Synch estrus synchronization protocol. On days -10, -3,0 (exogenously induced ovulation),7 and 14, transrectal ultrasonography was performed to evaluate ovarian structures, ensure synchrony, and determine the side of ovulation. Estrotect patches were applied on day -3, and cows with an activated patch (rubbed > 50%) on day 0 were considered to have displayed heat. Cows were harvested on day 15 and individual swabs were collected from each horn using aseptic techniques. DNA was extracted and the entire (V1-V9 hypervariable regions)16s rRNA gene was sequenced. Sequences were analyzed using the QIIME2 Pipeline. Burkholderiaceae, Chitinophagaceae, Rikenellaceae, Burkholderia, Rikenellaceae RC9 gut group, Lachnospiraceae AC2044 group, Vibrionimonas, Prevotellaceae UCG-001, and Rikenellaceae dgA-11 gut group abundances differed significantly (P < 0.05) in cows that exhibited estrus compared with non-estrual cows. In conclusion, there were significant differences in the composition of the microbial community between cows that exhibited estrus and non-estrual cows.