A Study on Bovine Mastitis, Isolation and Identification of Staphylococcus Species in Dairy Farms of Dire Dawa City, Eastern Ethiopia

摘要

Staphylococcal mastitis is the commonest and economically the greatest concern wherever dairyfarming is practiced. The chief reservoir of this bacterium is an infected udder. The organism is well adaptedto survive in the udder and usually establishes mild sub clinical infection of long duration. A cross-sectionalstudy was conducted from November 2014 to April 2015 to estimate prevalence of mastitis and to isolate andidentify Staphylococcus species in lactating dairy cows in selected dairy farms of Dire Dawa city. A total of334 milking cows (1336 quarters) tested using California Mastitis Test (CMT) and the prevalence at cow levelwas found to be 39.2% (131/334). Out of 131 positive cows, 84.73% (111/131) were subclinical mastitis cases andthe rest 15.27% (20/131) were clinical mastitis. Out of 1336 quarters examined, 296 were found to be positiveupon screening which account for the overall prevalence of 22.2% (296/1336) at quarter level. Out of 296positive quarters, 18.91% (56/296) and 81.08% (240/296) cases were from clinical and subclinical formsrespectively. From a total of 296 samples which were screening positive, 260 were found to be culture positive.From 260 culture positive samples, a total of 157 (60.4%) was positive for Staphylococcus species out of whichthe most prevalent being Staphylococcus aureus (S. aureus) (48.4%) followed by coagulase negativeStaphylococcus (34.4%), Staphylococcus intermedius (12.7%) and Staphylococcus hyicus (4.5%). The presenceof statistical significant association was assessed between the screening result and the risk factors like breed,parity and lactation stage and it was found to be statistically significant. Therefore, the result showed thatprevalence significantly differed with breed (P < 0.003), parity (P < 0.001) and lactation stage (P < 0.001). Thus,prevalence was relatively higher in exotic (Holstein Friesian) than local and cross breed, in cows with manycalves than those with moderate and few calves as well as in late and middle stage of lactation than early. Inconclusion, this study revealed the importance of mastitis and associated bacterial pathogen in the study area.