Sargeant J M, Scott H M, Leslie K E, Ireland M J, Bashiri A
Department of Population Medicine, University of Guelph, Ontario.
Can Vet J. 1998 Jan;39(1):33-8.
The objective of this study was to describe the frequency of occurrence of clinical mastitis in dairy herds in Ontario. The study group consisted of 65 dairy farms involved in a 2-year observational study, which included recording all clinical mastitis cases and milk sampling of quarters with clinical mastitis. Lactational incidence risks of 9.8% for abnormal milk only, 8.2% for abnormal milk with a hard or swollen udder, and 4.4% for abnormal milk plus systemic signs of illness related to mastitis were calculated for 2840 cows and heifers. Overall, 19.8% of cows experienced one or more cases of clinical mastitis during location. Teat injuries occurred in 2.1% of lactations. Standard bacteriology was performed on pretreatment milk samples from 834 cows with clinical mastitis. The bacteria isolated were Staphylococcus aureus (6.7%), Streptococcus agalactiae (0.7%), other Streptococcus spp. (14.1%), coliforms (17.2%), gram-positive bacilli (5.5%), Corynebacterium bovis (1.7%), and other Staphylococcus spp. (28.7%). There was no growth in 17.7% of samples, and 8.3% of samples were contaminated. Clinical mastitis is a common disease in dairy cows in Ontario; approximately 1 in 5 cow lactations have at lease one episode of clinical mastitis. There is, however, considerable variation in the incidence of clinical mastitis among farms. The majority of 1st cases of clinical mastitis occur early in lactation, and the risk of clinical mastitis increases with increasing parity. Environmental, contagious, and minor pathogens were all associated with cases of clinical mastitis.
本研究的目的是描述安大略省奶牛场临床型乳腺炎的发生频率。研究组由65个奶牛场组成，参与了一项为期2年的观察性研究，其中包括记录所有临床型乳腺炎病例，并对患有临床型乳腺炎的乳房区域进行牛奶采样。对2840头奶牛和小母牛计算得出，仅出现异常乳汁的泌乳发病率风险为9.8%，乳汁异常且乳房坚硬或肿胀的为8.2%，乳汁异常并伴有与乳腺炎相关的全身疾病症状的为4.4%。总体而言，19.8%的奶牛在定位期间经历了一例或多例临床型乳腺炎。2.1%的泌乳期发生了乳头损伤。对834头患有临床型乳腺炎奶牛的预处理牛奶样本进行了标准细菌学检测。分离出的细菌有金黄色葡萄球菌（6.7%）、无乳链球菌（0.7%）、其他链球菌属（14.1%）、大肠菌群（17.2%）、革兰氏阳性杆菌（5.5%）、牛棒状杆菌（1.7%）和其他葡萄球菌属（28.7%）。17.7%的样本没有生长，8.3%的样本被污染。临床型乳腺炎是安大略省奶牛的常见疾病；大约每5次奶牛泌乳中就有至少1次临床型乳腺炎发作。然而，各农场临床型乳腺炎的发病率存在相当大的差异。大多数临床型乳腺炎的首例病例发生在泌乳早期，且临床型乳腺炎的风险随着胎次增加而上升。环境性、传染性和次要病原体均与临床型乳腺炎病例有关。
