Associations of the first occurrence of pathogen-specific clinical mastitis with milk yield and milk composition in dairy cows
Associations of the first occurrence of pathogen-specific clinical mastitis with milk yield and milk composition in dairy cows
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DOI：
10.1017/s0022029918000456
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发表时间：
2018-08-01
影响因子：
2.1
通讯作者：
Grohn, Yrjo T.
中科院分区：
文献类型：
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作者：
Kayano, Mitsunori;Itoh, Megumi;Grohn, Yrjo T.
本研究的目的是估计首次发生病原体特异性临床乳腺炎（CM）与产奶量和乳成分（体细胞计数（SCC）、乳中乳糖、脂肪、蛋白质含量和乳尿素氮（MUN））的关系。我们研究了日本北海道31个奶牛场的3149头奶牛。研究了5组病原菌：链球菌；金黄色葡萄球菌（S. aureus）；凝固酶阴性葡萄球菌（CNS）；大肠杆菌群;和真菌。从2011年6月至2014年2月收集测试日牛奶数据和临床记录。采用自回归相关结构的混合模型拟合量化CM和其他几个控制变量（畜群、产犊季节、胎次、泌乳周和其他疾病）的影响。初产妇（第一次泌乳）和多产妇（第二次及以后泌乳）分别进行分析。所有病原体，特别是金黄色葡萄球菌和真菌，都与多期牛奶损失有关。在这项研究中，金黄色葡萄球菌和中枢神经系统感染与初产妇明显的乳汁流失无关。所有病原体，特别是金黄色葡萄球菌和真菌，在两个胎次组中显著增加SCC。所有病原体，特别是中枢神经系统（初产妇）和金黄色葡萄球菌（多产妇），乳糖含量降低。除真菌外，所有病原体组均与脂肪、蛋白质和MUN显著变化相关。一些病原体，如链球菌和大肠菌群似乎与长期的脂肪、蛋白质和MUN变化有关。这些发现提供了可用于计算CM精确成本的估计，也提供了更好的病原体特异性乳腺炎指标。
The aim of this study was to estimate the associations of the first occurrence of pathogen-specific clinical mastitis (CM) with milk yield and milk composition (somatic cell count (SCC), lactose, fat, protein content in milk and milk urea nitrogen (MUN)). We studied 3149 dairy cows in 31 Hokkaido dairy farms in Japan. Five pathogen groups were studied: Streptococcus spp.; Staphylococcus aureus (S. aureus); coagulase-negative staphylococci (CNS); coliforms; and fungi. Test-day milk data and clinical records were collected from June 2011 until February 2014. Mixed models with an autoregressive correlation structure were fitted to quantify the effects of CM and several other control variables (herd, calving season, parity, week of lactation, and other diseases). Primipara (first lactation) and multipara (second and later lactations) were analysed separately. All pathogens, particularly S. aureus and fungi, were associated with significant milk losses in multipara. In this study, S. aureus and CNS infections were not associated with significant milk loss in primipara. All pathogens, in particular S. aureus and fungi, significantly increased SCC in both parity groups. All pathogens, especially CNS (in primipara) and S. aureus (in multipara), decreased lactose content. All pathogen groups except for fungi were associated with significant changes in fat, protein and MUN. Some pathogens such as Streptococcus spp. and coliforms seemed to be associated with long-term fat, protein and MUN changes. These findings provide estimates that could be used to calculate precise costs of CM, and also provide better indicators of pathogen-specific mastitis.