OVINE MASTITIS, ASSOCIATED RISK FACTORS AND ANTIMICROBIAL RESISTANCE PATTERNS OF ISOLATES AROUND DEBRE BERHAN, NORTH CENTRAL HIGHLAND OF ETHIOPIA

Abstract

This study was carried out between March 2016 and August 2016 to estimate prevalence of mastitis, identify associated risk factors, to identify and isolate causative bacterial pathogens and to assess their antibiotic sensitivity patterns in smallholder dairy farms at Basona Warana district around Debre Berhan, North Shewa Zone, Ethiopia. Purposive sampling was followed to select the study area, Basona Warana district, based on its dairy potential and infrastructure facilities. Simple random sampling technique was used to select dairy farms. Accordingly, among 1500 smallholder dairy farms in the study area, 187 smallholder dairy farms were selected based on the list of the farmers from the dairy cooperatives of the district. A total of 187 herds were examined, of which 79.7% [95% CI: 73.9% - 87.4%] herds had mastitis, in which 10.7% and69% had clinical and subclinical mastitis, respectively. A total of 403 lactating cross breed lactating cows were selected and examined by physical examination of udder and milk and using California Mastitis Test (CMT). Out of the total examined cows 73.2% [95%CI: 68.2%-78.3%] had mastitis, of which 26% and 67.2% had clinical and subclinical mastitis, respectively. Out of 1612 examined quarters, 47.6% [95%CI: 44-51.2] quarters were mastitis positive, in which 21.7%, 47.6% and were clinical and subclinically positive, respectively. From the total examined quarters 1.1 % quarters [95%CI: 0.6-1.7] were blind teat. Association of bovine mastitis with different risk factors was checked using logistic regression model. The multivariable analysis revealed that the odds of being infected with mastitis were higher in cow with large parity number (OR=1.8) than cows with low parity number. The multivariable analysis also showed the odds of acquiring mastitis was higher in cows those washed every day (OR= 4.9) than cows washed with long gap and the risk of the disease was higher in cows with >3 lactating cow per herd (OR= 1.8) than cows with <3 lactating cow per herd. The predominant bacteria isolated were Staphylococcus spp 71.1% followed by Streptococcus spp 23% while E. coli 2.9% was the least isolates. The antimicrobial sensitivity test result showed that most of the isolated bacteria were found to be sensitive to Gentamicine, Kanamayacin, Streptomycin, Erythromycin and Penicillin G. Nevertheless, the isolates were resistant to Amoxicillin. The present study shows subclinical form of mastitis is highly prevalent in the study area. Stage of lactation, frequency of cow washing and number of lactating cow per herd were risk for mastitis. Staphylococcus spp were the most dominant isolates followed by streptococcus spp. Hence, attention should be given at later lactation by using dry cow therapy, proper washing and drying of cows and handling manageable size of herds and appropriate use of antimicrobial drugs could reduce the high prevalence mastitis in the study area.