Gulliksen S M, Lie K I, Sølverød L, Østerås O
Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science, Oslo, Norway.
J Dairy Sci. 2008 Feb;91(2):704-12. doi: 10.3168/jds.2007-0450.
The objectives of the present study were to evaluate colostrum quality in Norwegian dairy cows based on IgG content, and to identify associations between possible risk factors and low colostral IgG. A longitudinal cross-sectional survey on calf health in Norway was performed between June 2004 and December 2006. The participating dairy herds were randomly selected among herds registered in the Norwegian Dairy Herd Recording System as having at least 15 cow years. The participating farmers were requested to sample 10 mL of colostrum from the first milking after calving from 12 cows that had calved during the defined project period of 365 d. Colostrum samples from 1,250 cows from 119 herds were collected. The material consisted of 451, 337, 213, and 249 samples collected from cows in their first, second, third, and fourth parity or more, respectively. Analysis was performed on IgG content by using single radial immunodiffusion. Mixed models with herd as a cluster were fit by using grams of IgG per liter of colostrum as the dependent variable for the statistical analyses. The IgG content in the colostrum sampled ranged from 4 to 235 g/L, with a median of 45.0 g of IgG/L, with the 10th, 25th, 75th, and 90th percentiles being 23.1, 31.4, 63.6, and 91.6 g of IgG/L, respectively. Altogether, 57.8% of the samples contained less than the desired 50 g of IgG/L of colostrum. Cows in their fourth parity or more were found to have significantly higher levels of IgG per liter of colostrum than cows in their first or second parity. Colostrum from cows in their second parity had the lowest level of IgG. Cows calving during the winter months (December, January, and February) produced colostrum with a significantly lower IgG content compared with cows calving in any other season of the year. Somatic cell count, measured after calving, was significantly higher in cows producing colostrum of inferior quality compared with those producing high-quality colostrum. Of the total variation in colostrum quality, 13.7% could be explained by cluster effects within herd. The variation in IgG content in colostrum produced by Norwegian dairy cows indicates a need for improved colostrum quality control and subsequent adjustment of the colostrum feeding regimen to ensure a protective immunological status for newborn calves.
本研究的目的是基于免疫球蛋白G（IgG）含量评估挪威奶牛的初乳质量，并确定可能的风险因素与初乳低IgG之间的关联。2004年6月至2006年12月期间在挪威进行了一项关于犊牛健康的纵向横断面调查。参与的奶牛场是从挪威奶牛群记录系统中登记的至少有15个母牛年的牛群中随机选取的。要求参与的养殖户从在规定的365天项目期内产犊的12头母牛产后第一次挤奶中采集10毫升初乳。收集了来自119个牛群的1250头母牛的初乳样本。该材料分别由从第一胎、第二胎、第三胎和第四胎及以上母牛采集的451、337、213和249个样本组成。通过单扩散免疫比浊法对IgG含量进行分析。以每升初乳中IgG的克数作为统计分析的因变量，采用以牛群为聚类的混合模型。所采集初乳中的IgG含量范围为4至235克/升，中位数为45.0克IgG/升，第10、25、75和90百分位数分别为23.1、31.4、63.6和91.6克IgG/升。总体而言，57.8%的样本所含初乳中的IgG低于所需的50克/升。发现第四胎及以上的母牛每升初乳中的IgG水平显著高于第一胎或第二胎的母牛。第二胎母牛的初乳中IgG水平最低。与在一年中任何其他季节产犊的母牛相比，在冬季月份（12月、1月和2月）产犊的母牛所产初乳的IgG含量显著更低。产后测量的体细胞计数显示，与生产高质量初乳的母牛相比，生产劣质初乳的母牛体细胞计数显著更高。在初乳质量的总变异中，13.7%可由牛群内的聚类效应解释。挪威奶牛所产初乳中IgG含量的差异表明需要改进初乳质量控制，并随后调整初乳喂养方案，以确保新生犊牛具有保护性免疫状态。
