A Review of the Diversity of the Genital Tract Microbiome and Implications for Fertility of Cattle

SIMPLE SUMMARY: Reproductive systems of cattle contain multiple microbes resident in the female from a young age. Sometimes other harmful microbes can invade the genital tract and cause diseases that impair fertility. Normally, commensal microbes facilitate genital tract homeostasis and produce factors that stimulate male sexual response. For this reason, the type and number of microbes present in the genital tract are important for reproductive tract health, and any disruption of this microbial balance leads to genital diseases. Interestingly, these microbes frequently populate the genital tract of cows, leading to reproductive diseases that perturb fertility. However, a microbiome composed of commensal microbes will likely result in the restoration of uterine health and improved fertility of the cows. ABSTRACT: Cattle have a genital microbiome that is established early in life, even before calving. Microbial influx into the reproductive system of cows, during calving or mating, is unavoidable and is likely to alter the commensal microflora composition. It is now well established that a commensal endometrial flora is largely responsible for the overall fertility of cows. These microbes are important for maintenance of structural integrity of the genital mucosal barrier, immunomodulation, and protection against pathogens. Further, the genital microbiome functions in the semiochemical communication between a male and female. An optimal balance between the abundance and diversity of the microbiome is essential to promote female genital tract health. Disruption of this balance leads to dysbiosis and genital diseases and perturbed fertility. As part of the global strategy of One World, One Health, there is a need to reduce antibiotic use in animals. This area of research has the potential to expand the knowledge about the nexus between the endometrial microbiome and fertility including being probiotic in different species.