Bovine Uterine Microbiota and Endometritis: Ecological Characteristics, Host Interactions, Inflammatory Regulation,...

Bovine endometritis remains one of the most significant postpartum uterine disorders. It impairs uterine recovery, compromises fertility, and causes substantial economic losses in dairy production. Growing evidence suggests that the disease cannot be attributed solely to postpartum bacterial contamination; rather, it should be understood as a multifactorial failure to restore uterine homeostasis after calving. This review summarises the latest research findings on six interconnected aspects: the clinical significance of postpartum uterine disease; the diagnostic and biological differences between clinical and subclinical endometritis; the role of microbes in the uterus in health and disease; interactions between the host and uterine bacteria; the mechanisms of persistent inflammatory regulation; and current as well as emerging treatment strategies. Current evidence indicates that postpartum uterine disease is more strongly associated with dysbiosis, reduced microbial diversity, and disturbed microbial succession than with the presence of any single pathogen. Disease progression is driven by complex interplay among microbial ligands, epithelial and stromal immune responses, virulence-associated tissue injury, endocrine disruption, and impaired inflammatory resolution. Furthermore, persistent uterine inflammation is regulated by multilayered networks involving cytokines, prostaglandins, noncoding RNAs, extracellular vesicles, metabolic remodeling, and oxidative stress. Although conventional therapies remain relevant in certain clinical cases, microbiota-oriented approaches, particularly probiotic interventions, have emerged as promising adjunctive strategies for the prevention and control of the condition. Overall, bovine endometritis should be viewed as a disorder caused by disrupted interactions between the host, microbiota and inflammation. Future progress will depend on longitudinal, strain-resolved, and function-oriented studies to enable more precise and less antimicrobial-dependent interventions for postpartum uterine health.