Study on Prevalence of Bovine Mastitis and Associated Risk Factors in Dairy Farms of Modjo Town and Suburbs, Central Oromia, Ethiopia

Background: In the global dairy industry, mastitis is the main economic significant disease of cattle. Milk and other dairy outputs are scarce in developed countries, including Ethiopia. Methods: In this cross-sectional investigation in the Modjo district, milk samples were collected aseptically from 384 randomly selected lactating cattle to investigate the prevalence of clinical and sub-clinical mastitis and determine the possible risk factors and isolate bacterial pathogens causing mastitis. Besides, clinical mastitis cases have been reported by veterinarians based on milk, udder, or systemic cow anomalies, whereas the presence of subclinical mastitis was determined using California Mastitis Test (CMT). Results: The research revealed that subclinical mastitis (71.02%) is more prevalent in dairy farms of the study area than in the clinical type (28.9%). The quarter-level frequency was 36.9%; from which, 34.9% and 3.4% were from subclinical form and blind teat, respectively. There was a significant correlation between the frequency of mastitis in lactating cows (p < 0.05) and factors, such as breed, age, body condition score, herd size, milking mastitic cow at the end, and previous mastitis history. The dominant mastitis-causing agents isolated in this study were Staphylococcus aureus (40.3%), Streptococcus species (24.3%), Coagulase-negative Staphylococcus (12.5%), E. coli (8.3%), Staphylococcus hyicus (3.5%), and Staphylococcus intermedius (1.4%). The high occurrence of mastitis, particularly sub-clinical mastitis, revealed significant economic potential losses in dairy farms in the research district. Conclusion: Therefore, appropriate measures aimed at increasing the understanding and hygiene milking methods of dairy farmers, routine monitoring for subclinical mastitis, dry cow therapy, and culling of chronically contaminated cows to reduce bovine mastitis and its impact on milk production and food security.