Interpretive Summary: Uterine and vaginal bacterial community diversity prior to artificial insemination between pregnant and nonpregnant postpartum cows
By: Anne Wallace
The microbiome is comprised of a variety of organisms including bacteria, fungi and viruses. Of these, bacteria are the most well studied. Although some bacteria may be harmful, others are beneficial to their host and may even improve health or fertility. Any disruption to a microbial ecosystem within a living host is known as dysbiosis. Dysbiosis is also increasingly being linked to a number of diseases. The reproductive system also has its own unique microbial community, but the reproductive microbiome of heifers and how it relates to fertility is not well studied.
In this study published in the October 2019 issue of the Journal of Animal Science, researchers characterized the reproductive microbiomes (uterus and vagina) of female cows to determine how the bacterial members of these microbiomes may be correlated with fertility. They hypothesized that microbiomes would differ in pregnant versus non-pregnant cows.
A total of 68 postpartum cows were artificially inseminated and their reproductive microbiomes sampled for 30 days. Results indicated that cows who became pregnant had distinctly different microbiomes from cows who did not become pregnant after artificial insemination.
Overall, this study suggests that bacteria within the reproductive microbiome of cows may have an effect on fertility. Whether the bacteria are causal or simply correlated with increased fertility is yet to be determined. More in-depth studies to further characterize the types of microbial species clustering during pregnancy, correlate these species with increased fertility, and perhaps understand mechanisms behind such observations (e.g. measuring hormones or inflammatory markers) is warranted.