Intestinal microbiota dysbiosis in bovine mastitis: Its role and strategies for prevention and control targeting intestinal microbiota

Mastitis in dairy cattle persists as a significant global challenge, imposing substantial economic losses and compromising animal welfare. Conventional antibiotic-based protocols remain clinically effective when aligned with evidence-based antimicrobial stewardship guidelines. Nevertheless, the global rise in antimicrobial resistance and increased regulatory scrutiny of antibiotic residues in milk are intensifying efforts to develop non-antibiotic disease-control strategies. Concurrently, research attention has increasingly focused on the intestinal microbiota as a key regulator of systemic host physiology, affecting not only nutrient absorption but also distant organ functions through microbe-derived metabolites and immune signaling. Accumulating evidence, largely derived from non-bovine models, suggests that the gut microbiota interact with distant organs through intricate gut–organ axes. Pertinent to lactation physiology, the emerging concept of the gut–mammary axis suggests the existence of a potential communication pathway connecting the gastrointestinal tract and the mammary gland. Although emerging research still relies primarily on correlational evidence and non-bovine animal models, an increasing number of in vivo bovine datasets are beginning to elucidate how gut microbiota dysbiosis affects mammary function and susceptibility to inflammation. This review synthesizes current understanding of the complex relationship between gut dysbiosis and mastitis in dairy cows, detailing the gut–mammary axis concept and examining how gut microbial dysbiosis may initiate or exacerbate mastitis through biological mechanisms such as metabolite signaling, immune modulation, and intestinal epithelial barrier dysfunction. Building upon these insights, we explore prevention and control strategies centered on restoring and maintaining gut microbial homeostasis. An enhanced understanding of the gut–mammary axis may guide the development of microbiota-oriented interventions, offering a promising new research framework for sustainable mastitis management. However, further research, especially controlled longitudinal studies, is required to validate these approaches and assess their practical feasibility for enhancing bovine health and production efficiency.