慶北地方 乳牛乳房炎의 疫學的 調査 및 治療對策에 關한 硏究

Epidemiological Investigation on Mastitis of Milk Cows in Kyoung-buk Area

A total of 920 dairy cattle were examined for mastitis by California mastitis test (CMT) method. Milk samples from cattle infected with mastitis were studied bacteriologically and, among isolates, streptococci and staphylococci further examined for susceptibility to various antibiotics. The results obtained were as followings: Four hundred and seventy eight (52.0%) of 920 dairy cattle and 765(21.0%) of 3,642 quarters were positive for mastitis by CMT. It was also found that 395(85.7%) of the infected cattle were subclinical mastitis. A total of 261 strains of etiological agent were isolated from 254 quarters which showed CMT score (艹) or more. The important causative organisms were found to be Streptococcus agalactiae (34.1%) and Staphylococcus aureus (22.6%), and other streptococcus, S. epidermidis, coliform, pseudomonas, corynebacterium and yeast were also occasionally found to be causative agents. One hundred and forty five strains of streptococcus and 71 strains of staphylococcus were further examined for susceptibility to 9 antibiotics. Majority of strains were sensitive to kanamycin and leucomycin, and resistant to colistin, penicillin and streptomycin.