Rainard P, Ducelliez M, Poutrel B
Institut National de la Recherche Agronomique, Unité de Recherches sur les Mammites, Nouzilly, France.
Vet Res Commun. 1990;14(3):193-8. doi: 10.1007/BF00347737.
Quarter foremilk samples were taken at 2-3 weekly intervals for several years in an experimental herd comprising about 45 cows. The samples were submitted to bacteriological analysis and somatic cell counting. The most prevalent quarter infections from 1982 to 1988 were by coagulase-negative staphylococci (15-20% of all the quarters sampled). Most of these (75.6%) persisted until drying-off. Dry cow therapy eliminated 86.5% of these infections. Comparison of udder quarters within cows, involving 775 samples from pairs of non-infected quarters and quarters infected by coagulase-negative staphylococci, yielded geometric means of somatic cell counts of 210,000 and 420,000 cells/ml, respectively. The correlation (r = 0.87) between the herd bulk milk somatic cell count (SCC) and its estimation from the quarter milk somatic cell count performed on the same day allowed us to evaluate the contribution of the different categories of quarters, according to their infection status, to the herd bulk milk SCC. Quarters infected by a major pathogen (8.5% of samples) gave rise to 46.6% of the total number of cells, while quarters infected by coagulase-negative staphylococci (17.8% of samples) gave rise to 18.1%. Although coagulase-negative staphylococci represented only a secondary source of somatic cells as compared to major pathogens, they were not a negligible source considering the threshold of 300,000 somatic cells advocated for herd milk of good quality.
在一个约有45头奶牛的实验牛群中，连续数年每2至3周采集一次四分之一乳区的初乳样本。这些样本被送去进行细菌学分析和体细胞计数。1982年至1988年期间，最常见的乳区感染是由凝固酶阴性葡萄球菌引起的（在所有采样乳区中占15%至20%）。其中大多数（75.6%）一直持续到干奶期。干奶牛治疗消除了这些感染中的86.5%。对奶牛体内不同乳区进行比较，涉及775对样本，其中一对为未感染乳区，另一对为被凝固酶阴性葡萄球菌感染的乳区，其体细胞计数的几何平均值分别为每毫升210,000个和420,000个细胞。牛群批量牛奶体细胞计数（SCC）与其同一天对乳区牛奶体细胞计数的估计值之间的相关性（r = 0.87），使我们能够根据不同感染状态的乳区类别，评估它们对牛群批量牛奶SCC的贡献。被主要病原体感染的乳区（占样本的8.5%）产生的细胞总数占46.6%，而被凝固酶阴性葡萄球菌感染的乳区（占样本的17.8%）产生的细胞数占18.1%。尽管与主要病原体相比，凝固酶阴性葡萄球菌只是体细胞的次要来源，但考虑到优质牛群牛奶所倡导的300,000个体细胞的阈值，它们也不是一个可以忽略的来源。
