Studies of Infection Rate and Causative Agents of Bovine Mastitis in Chungnam Area

충남지역(忠南地域) 유우유방염(乳牛乳房炎)의 감염율(感染率) 및 원인균(原因菌)에 관한 연구(硏究)

A total of 820 dairy cattle were examined formastitis by California mastitis test method and 181 dairy cattle were examined bacteriologically according to the method of Connecticut mastitis control program. The results obtained were as followings: 1. Milk samples from 1.231(38.1%) of 3,225 quarters and 568(69.3%) of 820 dairy cattle were positive for mastitis by California mastitis test method. 2. Among 181 cattle examined bacteriologically by the method of Connecticut mastitis control program 159(22.9%) quarters of 102(56.4%) cattle were infected. Clinical mastitis was found in 5 cattle. 3. Important causative organisms were found to de Staphylococcus aureus(44.8%), Streptococcus agalactiae(21.5%), and non-str, agalactiae Streptococcus(26.4%). Corynebacterium ssp., Pseudomonas spp., Coliforms and Yeasts were also occasionally found to be causative organisms. 4. Strains of Staphylococcus aureus isolated from bovine udders were tested for sensitivity to antibiotics. The rates of resistant strain were 13.7%, 11.8%, 8.8%, 5.9%, 100%, 4.9% and 4.9% for penicillin G, streptomycin, terramycin, erythromycin, chloramphenicol, ampicillin and kanamycin, respectively.