Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell'Università 16, 35020 Legnaro, Padova, Italy.
Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Drive, Madison 53706.
J Dairy Sci. 2017 Dec;100(12):9775-9780. doi: 10.3168/jds.2017-13111. Epub 2017 Oct 12.
The aim of this study was to investigate the association between udder health (UH) status and blood serum proteins (i.e., total protein, albumin, globulin, and albumin-to-globulin ratio) in dairy cows. Blood and milk samples were collected from 1,508 cows of 6 different breeds (Holstein Friesian, Brown Swiss, Jersey, Simmental, Rendena, and Alpine Grey) that were housed in 41 multibreed herds. Bacteriological analysis was performed on milk samples with somatic cell count (SCC) >100,000 cells/mL and bacteria identification was confirmed by multiplex-PCR assays. Milk samples were grouped into 7 clusters of UH status: healthy (cows with milk SCC <100,000 cells/mL and not cultured); culture-negative samples with low, medium, or high SCC; and culture-positive samples with contagious, environmental, and opportunistic intramammary infections. Data of blood serum proteins were analyzed using a linear mixed model that included the fixed effects of stage of lactation, parity, breed, herd productivity (high or low production) and UH status, and the random effect of herd-date within herd productivity. Culture-negative samples with high milk SCC, which were most likely undergoing a strong inflammatory response and whose pathogens could not be isolated because they were engulfed by macrophages or because they had already cleared, and milk samples infected by contagious and environmental bacteria were associated with greater globulin concentrations (and lower albumin-to-globulin ratio) in blood. Variation in blood serum proteins seems to be associated with inflammatory status rather than infection, as serum globulin significantly increased in UH status groups with the highest milk SCC and no differences were observed among intramammary infections pathogens. Blood serum proteins can be a mammary gland inflammation indicator, but cannot be used to differentiate among different UH status groups.
本研究旨在探讨奶牛乳房健康（UH）状况与血清蛋白（即总蛋白、白蛋白、球蛋白和白蛋白/球蛋白比值）之间的关系。从 6 个不同品种（荷斯坦弗里生牛、瑞士褐牛、泽西牛、西门塔尔牛、雷登纳牛和阿尔卑斯灰色牛）的 1508 头奶牛中采集血液和牛奶样本，这些奶牛被安置在 41 个多品种牛群中。对牛奶样本进行细菌学分析，体细胞计数（SCC）>100,000 个细胞/mL 的样本进行细菌鉴定，并通过多重 PCR 检测确认。将牛奶样本分为 7 个 UH 状态组：健康（SCC<100,000 个细胞/mL 的奶牛，未培养）；低、中、高 SCC 的培养阴性样本；以及传染性、环境性和机会性乳腺炎感染的培养阳性样本。使用线性混合模型分析血清蛋白数据，模型中包括泌乳阶段、胎次、品种、牛群生产力（高或低产）和 UH 状态的固定效应，以及牛群生产力内的牛群日期随机效应。高 SCC 培养阴性样本可能正在经历强烈的炎症反应，其病原体由于被巨噬细胞吞噬或已经清除而无法分离，并且受传染性和环境性细菌感染的牛奶样本与血液中球蛋白浓度升高（白蛋白/球蛋白比值降低）相关。血清蛋白的变化似乎与炎症状态有关，而与感染无关，因为在 SCC 最高的 UH 状态组中，血清球蛋白显著增加，而乳腺炎感染病原体之间没有差异。血清蛋白可以作为乳腺炎症的指标，但不能用于区分不同的 UH 状态组。
