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

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.