Seasonal and Regional Dynamics of Mastitis Pathogens: Insights From a 3-Year Study in China

Mastitis is one of the biggest problems and an economic burden facing the dairy industry with a strong negative impact on animal welfare, productivity, and food safety. This study conducted a systematic investigation and analysis of the epidemiological characteristics of mastitis in selected regions of China (significant region for raw milk production). By collecting an extensive number of milk samples from clinical mastitis cases and utilizing methodologies such as bacterial isolation, genomic DNA extraction, and pathogen identification, the research elucidated the distribution patterns and trends of pathogenic bacteria responsible for mastitis across various regions and seasons. A total of 7177 milk samples were analyzed, identifying pathogenic bacteria in 3720 samples, which corresponds to a detection rate of 51.83%. Sixteen species of pathogenic bacteria were identified, with Klebsiella, coagulase-negative staphylococci (CoNS), and Escherichia coli (E. coli) being the predominant pathogens, representing 21.33%, 20.63%, and 18.72%, respectively. The study revealed significant seasonal and regional variations in the prevalence of pathogenic bacteria associated with mastitis. Detection rates of these bacteria were significantly higher in samples collected from May to September compared to other months, with September showing the highest detection rate at 85.94%. Furthermore, the southern region of China demonstrated the highest detection rate of pathogenic bacteria, with a prevalence of 94.98%. This study explored the pathogenicity and antimicrobial resistance profiles of the predominant bacterial strains, and proposed targeted prevention and control strategies based on these insights. The overarching aim is to provide a scientific basis for the effective management of mastitis, thereby alleviating the economic impact on the dairy farming industry.