Prevalence and etiology of subclinical mastitis inGhezel ewes in Nagadeh district, Iran

This study was conducted to determine the prevalence and etiology of subclinical mastitis in Ghezelewrs selected from 9 folks in Bahareh, Northwestern Iran. Collectively 146 milk samples from 73 ewes were taken for the California mastitis test( CMT), bacterial culture and antibiotic susceptibility of isolates. Samples from both glands of 37.73 (50.68℅) ewes had positive CMT results. Bacteria were isolated from 30.146(20.54℅) udder halves and 17.73(23.38℅) ewes. Prevalence rate of subclinical mastitis based on positive CMT and bacteriological results was 23.28℅ of examined ewes. A total of 30 isolates comprising escherichia coli 33.33℅ , staphylococcus aureus (16.66℅), staph. Epidermidis (16.66℅), staph. Intermedius(16.66℅) and streptococcus agalactiae (16.66℅) were identified. Antibiotic sensitivity testing revealed gentamicin to be the most effective antibiotic against all the of isolates, with 28.30(93.33℅) being susceptible. A positive correlation was found between CMT score and the age of ewe( p<0.01). The relationship between CMT score and the bacterial isolation rate was not statistically significant( p>0.05). It is concluded that for screening of subclinical mastitis in Ghezel sheep flicks, CMT test could be used with 100℅ sensitivity.