Prevalence and associated risk factors of Bovine mastitis in dairy cows in and around Assosa town, Benishangul-Gumuz Regional State, Western Ethiopia

Background: Mastitis, a complex disease of multifactorial aetiology, is one of the most costly diseases in the dairy industry worldwide. It can be categorized as clinical and subclinical type relying on the clinical sign. The objectives of the study were to determine the prevalence of mastitis and to identify its intrinsic and extrinsic risk factors in dairy cows in and around Assosa town, Western Ethiopia. Methods: A cross-sectional study design was followed to address the objectives of the study. A total of 367 lactating cows were selected using simple random and systematic sampling techniques. Thorough clinical examination and California Mastitis Test (CMT) were deployed for detection of both clinical and subclinical mastitis, respectively. Results: Based on CMT result and clinical examination the cow level prevalence of mastitis was 40.3% (n = 148), of which 11.99% (n = 44) and 28.34% (n = 104) were clinical and subclinical mastitis respectively. The corresponding quarter-level prevalence was determined to be 26.9% (n = 394), comprising 11.99% (n = 176) clinical and 14.85% (n = 218) subclinical mastitis. The Chi-square analysis of intrinsic risk factors revealed statistically significant differences (p <.05) in the prevalence of mastitis among breed, stage of lactation and body condition score. Likewise, production system, previous mastitis exposure, hygiene practice and type of floor were extrinsic risk factors significantly associated with the occurrence of mastitis. Conclusions: In general, this study revealed a high prevalence of bovine mastitis in the study area. Thus, the current study shows the need for applying feasible mastitis intervention strategy with special emphasis on sub-clinical mastitis and associated risk factors.