The Comparison Of The Vaginal Bacterial Microbiota In Healthy And Endometritis Dairy Cows

The vaginal bacterial flora plays a crucial role in the emergence and developmentof dairy cows’ endometritis, yet the diversity of the vaginal bacterial composition indairy cows and its connection with cows’ endometritis is still poorly understood. Thepurpose of this study was to use culture-independent methods to describe andcompare the vaginal bacterial composition in healthy and endometritis postpartumHolstein dairy cows.5healthy cows and5Unhealthy cows that were diagnosedwith endometritis,and were chosen from commercial dairy farm in Jiutai, Jilinprovince. Vaginal swab samples were collected at45days postpartum，and anintegrated approach based on16S rDNA, PCR-denaturing gradient gel electrophoresis(PCR-DGGE) and clone library sequencing was used to compare the structure anddiversity of bacterial communities. To quantify the levels of different genus ofbacterial detected by PCR-DGGE, a quantitative real-time PCR assay was developedand utilized to determine the differences in quantity. The results were as follows:The DGGE profiles revealed that the number of bands and diversity index ofendometritis detected dairy cows were significantly higher than that of healthy cows.The vaginal flora of healthy cow was dominated by Lactobacillus sakeisubsp.,Weissella koreensis sp. and Bacillus licheniformis, which were decreased ordisappeared under endometritis conditions. In the clone libraries from healthy andendometritis dairy cows, the sequences showed high identity with Bacteroides fragilis,Bacteroides helcogenes,Mycoplasma agalactiae,Prevotella dentalis,Clostridiumperfringens str., Enterococcus hirae.. The specific pathogen of Escherichia colistr.K-12substr. and Fusobacterium nucleatum subsp. detected by PCR-DGGEmethods were also found to exist at a low level in the reproductive tract of healthycow as well, it means we didn’t find any specific pathogen of endometritis. Theaverage percentage of Escherichia coli in sample of endometritis detected dairy cowswere significantly higher than that of healthy cows(P＜0.05)，apparently, it was themost dominating microorganism compared to other bacterial species, Therefore,Escherichia coli could be major pathogenic bacterium of dairy cows’ endometritis.Our results suggest that the vaginal bacterial composition in endometritis dairycows was more complex than that of healthy cows, and no specific pathogen wasdetected yet in the vaginal samples of endometritis detected dairy cows. The amplification of pathogen and ecological disorder of the vaginal microbiota couldassist in the presence of diagnosed dairy cows with Endometritis.