Contagious Mastitis: Prevalence, Risk Factors and Antibiotics Susceptibility Profile Study in Jimma Dairy Farms, South- West Ethiopia

Abstract

A study was conducted in Jimma town cross breed dairy farms to determine the prevalence contagious mastitis, risk factors and antimicrobial susceptibility profile of the isolates between October 2012 and May 2013 using California Mastitis Test (CMT) for screening subclinical mastitis. All milk samples were cultured for bacteriological identification by following the protocol described by National Mastitis Council. Clinical mastitis prevalence was determined through examination of abnormalities of milk, udder or cow during sample collection. Out of the 206 cows examined 101 cows were positive to mastitis. Out of 824 quarters examined, 50 (6.06%) were found blind and 774 quarters were found to be functional. Out of the total quarters examined, 404 (52.2%) were affected, 34 (8.4%) clinically and 370 (91.6%) sub clinically. Of 404 infected quarters, 57 quarters were found positive to contagious mastitis. The overall prevalence of contagious mastitis at cow and quarter level was 27.7% and 7.4% respectively. Potential risk factors for the occurrence of contagious mastitis were wood or soil floor type, source of water, milkers, lactation stage and purchasing heifers into herd. The pathogens isolated in this study were S. aureus and S. agalactiae, S. aureus was the most dominant species identified in this study area. Antimicrobial susceptibility tested was conducted on 57 isolates against seven antimicrobial agents for S.aurues and nine for s.agalactae. All strains were resistant to Amoxacilline +CLAV(30+15µg), Cefquinome, Streptomycin, Tetracycline (80µg), Trimethoprim +Sulfa(5.240µg) and polymyxin by 82.5% 3.5% ,7.0% ,42.1%, 3.5%,82.5% respectively. About 18.8% of S.agalactae isolates was resistant to Ampicillin (30 µg) and Enrofloxacin (10 µg) were resistant to. Good hygiene in milking process, creation of awareness for milkers on contagious mastitis, milking clinically infected cows at last, culling chronic mastitis carriers, treating clinically infected cows and dry period therapy could reduce the prevalence of contagious mastitis in the study area