Awardee Talk: Vaginal Microbiomes of Lactating Dairy Cattle Bred Utilizing Timed Artificial Insemination Or Estrus Expression
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
AbstractWithin the cattle industry, implementation of timed artificial insemination (TAI) or estrus detection protocols aid in determining the optimal breeding date. However, previous studies utilizing both breeding strategies have found differences between pregnancy rates, further emphasizing pregnancy establishment as a prominent issue in cattle production systems. Recent research has begun to evaluate the role of the female reproductive microbiome as it pertains to pregnancy establishment in cattle. It has been demonstrated that shifts in the female reproductive bacterial communities may alter pregnancy outcomes in cattle. Therefore, the objective of this work was to evaluate vaginal microbiomes on day of artificial insemination (AI) in dairy cattle bred utilizing either TAI or estrus detection and the impacts on subsequent pregnancy outcomes. Lactating Holstein cows (104 days in milk) were classified into two groups based on breeding protocols: 1) TAI (n = 44), and 2) Heat (n = 9). On day of AI, sterile swabs were inserted into the vagina, rotated eight times, and subsequently stored at -80C in sterile collection tubes for microbiome analysis. For microbiome analysis, the V4 hypervariable region of the 16S rRNA bacterial gene was targeted. Statistical analysis for microbiome data were conducted using PROC TTEST in SAS where equality of variances was performed. Pregnancy rates by TAI versus Heat were 56.8% and 33.3%, respectively. The phylum Firmicutes had greater relative abundance in cows bred by Heat (64.1 2.3% vs. 53.9 2.5%, respectively; P > 0.01) compared with phyla Proteobacteria (7.1 0.8% vs. 13.7 1.7%), Fusobacteria (0.9 0.3% vs. 5.8 1.5%), and Actinobacteria (1.8 0.3% vs. 3.2 0.5%) which had a greater relative abundance in cows bred by TAI (P > 0.01). Within Firmicutes, genera Ruminococcus (13.0 1.0% vs. 8.5 0.6%), Blautia (10.3 0.7% vs. 8.0 0.5%), Clostridium (5.8 0.2% vs. 4.9 0.3%), Oscillospira (2.2 0.2% vs. 1.7 0.1%), and Caloramator (2.1 0.1% vs. 1.7 0.1%) were all greater in relative abundance in cows bred by Heat compared with cows bred by TAI (P > 0.05). Interestingly, within Fusobacteria, genera Sneathia (0.6 0.3% vs. 3.5 1.0%) and Fusobacterium (0.2 0.1% vs. 1.5 0.5%) were greater in relative abundance in cows bred by TAI (P > 0.01). Within phyla Proteobacteria and Bacteroidetes, genera Gallibacterium and Porphyromonas respectively, were both greater in relative abundance in cows bred by TAI (P > 0.05). Collectively these results indicate that the vaginal microbiomes of lactating dairy cows bred via TAI or estrus expression differs. Additionally, a shift in the vaginal microbiome to a prevalence of the phylum Firmicutes on day of AI appears to be negatively impacting pregnancy outcomes.
