An Advanced Understanding of Uterine Microbial Ecology Associated with Metritis in Dairy Cows

Metritis, the inflammation of the uterus caused by polymicrobial infections, is a prevalent and costly disease to the dairy industry as it decreases milk yield, survival, and the welfare of dairy cows. Although the antibiotic ceftiofur is widely used for the treatment of metritis, endometrium and ovary function is compromised, resulting in subfertility and infertility. According to culture-dependent studies, uterine pathogens include Escherichia coli, Trueperella pyogenes, Fusobacterium necrophorum, and Prevotella melaninogenica. Recent studies using high-throughput sequencing claimed that metritis is a microbiota-associated disease. Herein, we propose that metritis is associated with uterine microbiota with high abundance of Bacteroides, Porphyromonas, and Fusobacterium, but rare bacteria such as Escherichia coli and Helcococcus ovis cannot be ignored.