Todhunter D A, Smith K L, Hogan J S
Department of Animal Sciences, Ohio Agricultural Research and Development Center, Ohio State University, Wooster 44691, USA.
J Dairy Sci. 1995 Nov;78(11):2366-74. doi: 10.3168/jds.S0022-0302(95)76864-3.
Characteristics of environmental streptococcal IMI were investigated over a 7-yr period for a herd in total confinement. A total of 374 new environmental streptococcal IMI was detected. Approximately 50.5% of IMI were new in the dry period, and 49.5% were new in lactation. The rate of new IMI was .00312 IMI/cow day during the dry period and .00054 IMI/cow day during lactation. The percentages of cows and quarters with an environmental streptococcal IMI present at calving were 10.6 and 3.2%, respectively. The percentage of heifers with an environmental streptococcal IMI at calving was similar to that for cows. The rate of new environmental streptococcal IMI was greater during the 1st mo of lactation than during the remainder of lactation. The rate of IMI during late lactation was higher for older cows than for either heifers or cows in second lactation. The rate of environmental streptococcal IMI during the dry period and during lactation was greatest during summer. The mean days of lactation that cows were infected for all IMI was 12.3 d. Approximately 41% of IMI had a duration of < 8 d. Stage of lactation, season of the year, and parity influenced the rate of new IMI.
对一个完全封闭牛群在7年期间的环境性链球菌引起的乳房炎（IMI）特征进行了调查。共检测到374例新的环境性链球菌引起的IMI。大约50.5%的IMI发生在干奶期，49.5%发生在泌乳期。干奶期新IMI的发生率为0.00312例/牛·天，泌乳期为0.00054例/牛·天。产犊时存在环境性链球菌引起的IMI的奶牛和乳腺的百分比分别为10.6%和3.2%。产犊时患有环境性链球菌引起的IMI的小母牛的百分比与奶牛相似。泌乳第1个月新环境性链球菌引起的IMI发生率高于泌乳期的其余时间。老龄奶牛在泌乳后期的IMI发生率高于小母牛或二胎奶牛。干奶期和泌乳期环境性链球菌引起的IMI发生率在夏季最高。所有IMI中奶牛感染的平均泌乳天数为12.3天。大约41%的IMI持续时间<8天。泌乳阶段、年份季节和胎次影响新IMI的发生率。
