PSIII-14 Reproductive Microbiome and Cytokine Profiles of Postpartum Beef Cows in Relation to Fertility

Shifts in commensal bacteria (i.e., Firmicutes) in the human microbiome are associated with compromised fertility. The objectives of this study were to characterize 1) the reproductive microbiome and 2) the cytokine concentrations prior to artificial insemination (AI) in vaginal and uterine flushes from postpartum beef cows. Twenty Bos indicus-influenced beef cows (~60 days postpartum and free of health issues) were weighed, body condition scored (BCS) then subjected to the Bee Synch II synchronization protocol on d-8 and timed AI on d0. Blood samples were collected on d-3, -1, 0, and 28. Vaginal and uterine flushes were collected on d-3 and d-1. On d28, pregnancy was determined by transrectal ultrasonography (Open, n=13 and Pregnant, n=7). Bacterial community analyses were conducted targeting the V4 hypervariable region of the 16S rRNA gene. Cytokine analyses were conducted using the RayBiotech Quantibody® Bovine Cytokine Array Q1 kit per manufacturer's instructions. Weight, BCS, and vaginal bacterial communities by phyla were not different (P >0.05). In open cows, the uterine relative abundance of Firmicutes decreased between d-3 and -1 (60.4% ± 0.9% vs. 48.5% ± 3.2%, respectively; P< 0.05). In pregnant cows, the uterine relative abundance of Tenericutes significantly increased between d-3 and -1 (1.0% ± 0.1% vs. 7.6% ± 4.1%, respectively; P< 0.05). Additionally, the genus Ureaplasma tended to increase in relative abundance from d-3 to -1 (0.1% ± 0.1% vs. 7.3% ± 4.9%, respectively; P=0.06). Uterine concentrations of Interferon (IFN)-γ, Interleukin (IL)-1α and IL-21 were greater in open females compared to pregnant. Vaginal concentrations for IFN-α and chemokine ligand (CXCL)-10 were greater in open females compared to pregnant. Regardless of treatment, IL-13 increased from d-3 to d-1. These results suggest a distinct difference in the uterine microbiome and cytokine profiles prior to AI for resulting pregnant and open cows.