Mechor G D, Gröhn Y T, McDowell L R, Van Saun R J
Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
J Dairy Sci. 1992 Nov;75(11):3131-5. doi: 10.3168/jds.S0022-0302(92)78076-X.
The effects of temperature and colostrum components on specific gravity in bovine colostrum were investigated. Thirty-nine first milking colostrum samples were collected from Holstein cows. The samples were assayed for alpha-tocopherol, fat, protein, total solids, and IgG. The concentrations of total solids, total protein, total IgG, and fat in colostrum were 26.6, 12.5, 3.7, and 9.4 g/100 g, respectively. A range of 1.8 to 24.7 micrograms/ml for alpha-tocopherol was measured in the colostrum samples. Specific gravity of the colostrum was measured using a hydrometer in increments of 5 degrees C from 0 to 40 degrees C. Specific gravity explained 76% of the variation in colostral total IgG at a colostrum temperature of 20 degrees C. The regression model was improved only slightly with the addition of protein, fat, and total solids. The model for samples at 20 degrees C was IgG (milligrams per milliliter) = 958 x (specific gravity) - 969. Measurement of specific gravity at variable temperatures necessitated inclusion of temperature in the model for estimation of IgG. Inclusion of the other components of colostrum into the model slightly improved the fit. The regression model for samples at variable temperatures was as follows: IgG (milligrams per milliliter) = 853 x (specific gravity) + .4 x temperature (Celsius degrees) - 866.
研究了温度和初乳成分对牛初乳比重的影响。从荷斯坦奶牛中采集了39份首次挤奶的初乳样本。对这些样本进行了α-生育酚、脂肪、蛋白质、总固体和免疫球蛋白G（IgG）的检测。初乳中总固体、总蛋白、总IgG和脂肪的浓度分别为26.6、12.5、3.7和9.4克/100克。在初乳样本中测得α-生育酚的含量范围为1.8至24.7微克/毫升。使用比重计在0至40摄氏度范围内以5摄氏度为增量测量初乳的比重。在初乳温度为20摄氏度时，比重解释了初乳中总IgG变异的76%。加入蛋白质、脂肪和总固体后，回归模型仅略有改善。20摄氏度样本的模型为：IgG（毫克/毫升）= 958×（比重） - 969。在不同温度下测量比重需要在IgG估计模型中纳入温度。将初乳的其他成分纳入模型后，拟合度略有提高。不同温度下样本的回归模型如下：IgG（毫克/毫升）= 853×（比重） + 0.4×温度（摄氏度） - 866。
