Nyman A-K, Emanuelson U, Holtenius K, Ingvartsen K L, Larsen T, Waller K Persson
Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89 Uppsala, Sweden.
J Dairy Sci. 2008 Aug;91(8):2996-3009. doi: 10.3168/jds.2007-0969.
The main objective of this study was to investigate associations between serum concentrations of several blood variables related to metabolic and immunological status around calving, and udder health measured as milk somatic cell counts (SCC), Box-Cox transformed to bcSCC, at first test-milking in 287 primiparous cows in 20 Swedish dairy herds. Possible systematic effects of breed and age at calving on blood profiles were also investigated. Ordinary linear regression models, with robust standard errors and adjusting for clustering within herds, were used to investigate associations between blood variables and bcSCC. Hierarchical linear regression models, with herd as random factor, were used to investigate systematic effects on blood variables. The results showed that greater concentrations of beta-hydroxybutyrate (BHBA) and glucose before calving were associated with lesser bcSCC at first test-milking, whereas greater concentrations of nonesterified fatty acids (NEFA) before calving and greater delta NEFA (describing the difference in concentrations before and after calving) were associated with greater bcSCC at first test-milking. In addition, greater alpha-tocopherol concentrations in the period -5 to +5 d relative to calving were associated with lesser bcSCC at first test-milking, whereas greater concentrations of collectin of 43 kDa (CL-43) postpartum (1 to 21 d after calving) were associated with greater bcSCC. Postpartum concentrations of conglutinin and haptoglobin were also associated with bcSCC, but not independently of each other. Moreover, significant breed differences were observed for insulin, urea nitrogen, conglutinin, cholesterol, NEFA, and CL-43, the latter 3 as an interaction with period. Overall, cows of the Swedish Red breed had greater concentrations of insulin, cholesterol, urea nitrogen, and conglutinin, and lesser concentrations of NEFA and CL-43 than cows of the Swedish Holstein breed. Age at calving as main effect was significantly associated with BHBA, glucose, insulin, NEFA, urea nitrogen, and conglutinin. Heifers calving at >27 mo of age had greater BHBA and NEFA values, and lesser glucose, insulin, and urea nitrogen values compared with heifers calving at <27 mo. Heifers calving at an age <25 mo had greater conglutinin and urea nitrogen values, and lesser NEFA values compared with heifers calving at >25 mo. The results show that there are several associations among metabolites, immunological variables, and udder health of primiparous cows, but also that these variables vary between breeds and between cows of different age at first calving.
本研究的主要目的是调查20个瑞典奶牛场287头初产奶牛产犊前后与代谢和免疫状态相关的几种血液变量的血清浓度，与首次挤奶时以牛奶体细胞计数（SCC）衡量的乳房健康之间的关联，SCC经Box-Cox变换为bcSCC。还研究了品种和产犊年龄对血液指标可能产生的系统影响。使用具有稳健标准误差并对牛群内聚类进行校正的普通线性回归模型，来研究血液变量与bcSCC之间的关联。以牛群为随机因素的分层线性回归模型，用于研究对血液变量的系统影响。结果表明，产犊前较高浓度的β-羟基丁酸（BHBA）和葡萄糖与首次挤奶时较低的bcSCC相关，而产犊前较高浓度的非酯化脂肪酸（NEFA）和较高的ΔNEFA（描述产犊前后浓度差异）与首次挤奶时较高的bcSCC相关。此外，相对于产犊的-5至+5天期间较高的α-生育酚浓度与首次挤奶时较低的bcSCC相关，而产后（产犊后1至21天）较高浓度的43 kDa凝集素（CL-43）与较高的bcSCC相关。产后的胶固素和触珠蛋白浓度也与bcSCC相关，但并非相互独立。此外，观察到胰岛素、尿素氮、胶固素、胆固醇、NEFA和CL-43存在显著的品种差异，后三者存在时期交互作用。总体而言，瑞典红牛品种的奶牛比瑞典荷斯坦品种的奶牛具有更高的胰岛素、胆固醇、尿素氮和胶固素浓度，以及更低的NEFA和CL-43浓度。产犊年龄作为主要效应与BHBA、葡萄糖、胰岛素、NEFA、尿素氮和胶固素显著相关。与产犊年龄小于27月龄的小母牛相比，产犊年龄大于27月龄的小母牛具有更高的BHBA和NEFA值，以及更低的葡萄糖、胰岛素和尿素氮值。与产犊年龄大于25月龄的小母牛相比，产犊年龄小于25月龄的小母牛具有更高的胶固素和尿素氮值，以及更低的NEFA值。结果表明，初产奶牛的代谢物、免疫变量和乳房健康之间存在多种关联，而且这些变量在不同品种和首次产犊时不同年龄的奶牛之间存在差异。
