Abstract The combined use of somatic cell count (SCC) and differential somatic cell count (DSCC), which is the ratio of neutrophils plus lymphocytes to total milk SCC, represents a novel approach to define cow’s udder health status, as it allows to identify healthy animals (those with low SCC and DSCC), cows susceptible to mastitis (those where an immune response has begun, so that there is an increase of neutrophils, i.e. DSCC, but not yet of total SCC), animals with a mastitic event in progress (those with high SCC and DSCC) and animals with possible chronic inflammation (those with high SCC and low DSCC, as macrophages prevail). We investigated the association of cow’s udder health status with milk yield, composition and coagulation properties in four cattle breeds. Results demonstrated that milk traits vary among cows with different udder health status, especially in terms of fat percentage, lactose percentage and coagulation ability. The most pronounced worsening in milk yield and coagulation ability was observed for animals with chronic inflammation. Our findings support the new approach based on the combined use of SCC and DSCC to screen for cow’s udder health, as it would allow to identify susceptible cows that will probably undergo a mastitic event and chronic cows that would possibly reduce the herd milk production and quality. Highlights The combined use of SCC and DSCC is a novel approach to screen for udder health status. Differences in milk yield, composition and coagulation exist among cows with different udder health status defined on the basis of combined SCC and DSCC. The information about udder health status may be used to develop mastitis pre-screening protocols.

中文翻译：

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结合体细胞总数和体细胞计数，更好地评估乳房健康状况与奶牛产奶量、成分和凝血特性的关联

摘要 体细胞计数 (SCC) 和体细胞分类计数 (DSCC) 的组合使用，即中性粒细胞加淋巴细胞与总牛奶 SCC 的比率，代表了一种定义奶牛乳房健康状况的新方法，因为它允许识别健康动物（具有低 SCC 和 DSCC 的那些），易患乳腺炎的奶牛（那些已经开始免疫反应，因此中性粒细胞增加，即 DSCC，但尚未增加总 SCC），正在发生乳腺炎的动物（具有高 SCC 和 DSCC 的动物）和可能具有慢性炎症的动物（具有高 SCC 和低 DSCC 的动物，因为巨噬细胞占优势）。我们调查了奶牛乳房健康状况与四个牛种的产奶量、成分和凝血特性之间的关联。结果表明，不同乳房健康状况的奶牛的牛奶性状存在差异，尤其是脂肪百分比、乳糖百分比和凝血能力。观察到慢性炎症动物的产奶量和凝血能力恶化最明显。我们的研究结果支持基于联合使用 SCC 和 DSCC 来筛查奶牛乳房健康的新方法，因为它可以识别可能会发生乳腺炎的易感奶牛和可能会降低牧群牛奶产量和质量的慢性奶牛. 亮点 联合使用 SCC 和 DSCC 是一种筛查乳房健康状况的新方法。根据 SCC 和 DSCC 组合定义的不同乳房健康状况的奶牛在产奶量、成分和凝血方面存在差异。