Prevalence and risk factors of bovine mastitis in Ambo town of West Shewa Zone, Oromia, Ethiopia

A cross-sectional study was conducted to estimate the prevalence and associatedrisk factors of mastitis in dairy cows from November, 2012 to July, 2013 in Ambotown of West Shewa Zone, Oromia Regional State. Thorough clinical examinationwas made on all lactating cows for evidence of signs of clinical mastitis followedby collection of milk sample for examination of gross changes of milk secretionand screening using California Mastitis Test (CMT). Mastitis was categorized asclinical if lactating cows exhibited clinical features of mastitis, or subclinical basedon degree of coagulation up on examination using CMT. A total of 151 dairy cowswere selected from all volunteer dairy farms in Ambo town of West Shewa Zone ofOromia region state. Sixty three (41.7%) cows had mastitis, of which 9.9% (15/151) were clinical and 31.8% (48/151) were subclinical mastitis cases. The quarter level prevalence was 44.4% (268/604), comprising 9.3% (56/604) clinical and 31.8% (198/604) subclinical forms of mastitis. In addition, 5.5% (33/604) of teats were found to be blind up on clinical examination of udder and teat. The Chi-square (χ2) analysis of intrinsic risk factors revealed significantly (P<0.05) higher prevalence of mastitis in crossbred cattle (47.2%) than indigenous (15.4%), in cattle above 7 years (75%) than less than 2-6 years of age (28%) and cows given more than 4 calves (81.3%) than those with less than 4 calves (31.1%) irrespective to their lactation stage. There was also significantly (P<0.05) higher mastitis prevalence in larger (46.6%) than smaller herds (24.2%) and among the farming systems in semi-intensive (47.1%) and intensive (42.3%) than extensive (8.1%) management system. The present study indicated higher prevalence of mastitis linked with several risk factors. Thus, early diagnosis and regular screening of cows for subclinical mastitis together with treatment of clinical cases are of paramount importance. Moreover, control and prevention strategies should be  designed and implemented with great emphasis given to risk factors to reduce bovine mastitis and its impact on milk production and food security.Keywords: Ambo town, CMT, Dairy Cows, Mastitis, Prevalence, Risk factors