Lievaart J J, Barkema H W, Kremer W D J, van den Broek J, Verheijden J H M, Heesterbeek J A P
Department of Farm Animal Health, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands.
J Dairy Sci. 2007 Sep;90(9):4137-44. doi: 10.3168/jds.2006-847.
In this study, the contribution of management practices, herd characteristics, and seasonal variables to the herd somatic cell count (SCC) was quantified in herds with low (<150,000 cells/mL), medium (150,000-200,000 cells/mL), and high (>200,000 cells/mL) herd SCC (HSCC). Selection of the variables was performed using a linear mixed effect model; HSCC was calculated as the arithmetic mean of the individual cow's SCC. The data concerning management practices were derived from 3 questionnaires on mastitis prevention and management practices on 246 Dutch dairy farms. The monthly Dairy Herd Improvement test data of these 246 farms were used to calculate the herd characteristics and seasonal effects. None of the management practices were associated with HSCC in all 3 HSCC categories. Some variables only had a significant association with HSCC in one HSCC category, such as dry premilking treatment (-9,100 cells/mL in the low HSCC category) or feeding calves with high SCC milk (11,100 cells/ mL in the medium HSCC category). Others had an opposite effect on HSCC in different HSCC categories, such as average parity (-6,400 and 11,000 cells/mL in the low and medium HSCC category, respectively) and feeding calves with fresh milk (10,300 and -9,700 cells/ mL in the low and high HSCC category, respectively). We conclude that, given the individual Dairy Herd Improvement data and information on management practices of an individual farm, it is possible to provide quantitative insight into the contribution of these different variables to the HSCC of an individual farm. Being able to provide such insight is a prerequisite for interpretation, prediction, and control of HSCC on individual dairy farms.
在本研究中，对体细胞数低（<150,000个细胞/毫升）、中（150,000 - 200,000个细胞/毫升）和高（>200,000个细胞/毫升）的奶牛群体，量化了管理措施、牛群特征和季节变量对群体体细胞计数（SCC）的影响。变量的选择使用线性混合效应模型；群体SCC以个体奶牛SCC的算术平均值计算。关于管理措施的数据来自对荷兰246个奶牛场乳腺炎预防和管理措施的3份调查问卷。利用这246个农场的月度奶牛群改良测试数据计算牛群特征和季节效应。在所有3个群体SCC类别中，没有一种管理措施与群体SCC相关。一些变量仅在一个群体SCC类别中与群体SCC有显著关联，如干奶期挤奶前处理（在低群体SCC类别中为 -9,100个细胞/毫升）或用高SCC牛奶喂养犊牛（在中群体SCC类别中为11,100个细胞/毫升）。其他一些变量在不同的群体SCC类别中对群体SCC有相反的影响，如平均胎次（在低和中群体SCC类别中分别为 -6,400和11,000个细胞/毫升）以及用新鲜牛奶喂养犊牛（在低和高群体SCC类别中分别为10,300和 -9,700个细胞/毫升）。我们得出结论，鉴于个体奶牛群改良数据和单个农场的管理措施信息，有可能定量了解这些不同变量对单个农场群体SCC的贡献。能够提供这样的见解是解释、预测和控制单个奶牛场群体SCC的先决条件。
