299 Differences in Microbial Community Composition between Uterine Horns Ipsilateral and Contralateral to the Corpus Luteum in Beef Cows on day 15 of the Estrous Cycle

Abstract The objective of this study was to evaluate the uterine microbiota composition cows on day 15 estrous cycle. Non-pregnant Bos taurus beef (n = 23) were exposed a pre-synchronization step followed by 7-d CO-Synch estrus synchronization protocol. On days -10, -3, 0 (exogenously induced ovulation), 7 and 14, transrectal ultrasonography performed ovarian structures, ensure synchrony, determine side ovulation. Cows harvested individual swabs collected from each horn using aseptic techniques. DNA extracted entire (V1-V9 hypervariable regions) 16s rRNA gene sequenced. Sequences analyzed QIIME2 Pipeline. Across all samples, 22 phyla, 130 families, 215 genera, 90 different species identified. Butyrivibrio, Bacteroidales RF16 group, Clostridia_UCG-014, Moraxellaceae, had (P < 0.05) relative abundances in ipsilateral compared with contralateral horns, whereas Proteobacteria, Acinetobacter, Bradyrhizobium, Lachnospiraceae FCS020 Nanoarchaeota, Woesearchaeales, Prevotellaceae YAB2003 group tended 0.10) differ between horns. In conclusion, there significant differences microbial community