Reksen O, Havrevoll O, Gröhn Y T, Bolstad T, Waldmann A, Ropstad E
Norwegian School of Veterinary Science, Department of Reproduction and Forensic Medicine, Oslo.
J Dairy Sci. 2002 Jun;85(6):1406-15. doi: 10.3168/jds.S0022-0302(02)74208-2.
Relationships among body condition score (BCS), milk constituents, and resumption of postpartum luteal function were studied in 162 lactations of first- and second-parity Norwegian dairy cows. Milk components included acetone, lactose, fat, protein, urea, and ratios of fat to protein and fat to lactose. Milk progesterone concentrations were used to determine intervals from calving to first luteal response (> 5 ng/ml). Intervals to first luteal response were divided into categories of early (< or = 24 d) or late (> 24 d) responses. Higher BCS were observed during wk 4 and 5 postpartum among both first- and second-parity cows with early compared with delayed luteal responses. Second-parity cows with early onset of luteal function also had higher BCS from wk 6 through 12, whereas first-parity cows with early onset of luteal function had higher BCS from wk 13 through 15. Higher acetone levels from wk 2 through 4 postpartum were associated with late luteal response in second-parity cows. Greater milk lactose content during wk 1, 2, 3, 6, 7, and 8 postpartum and higher fat fractions during wk 4 postpartum were related to early luteal response in second-parity cows. Relationships between milk constituents and onset of luteal function were less evident and occurred later postpartum among first-parity cows than among second-parity cows. Measures of weekly milk composites obtained during the early postpartum period and BCS were closely associated with postpartum resumption of luteal function. Acetone and lactose values in milk from the first 4 wk postpartum predicted postpartum luteal function in second-parity cows at a sensitivity of 0.84 and specificity of 0.86.
在162头初产和经产挪威奶牛的162次泌乳期内，研究了体况评分（BCS）、乳汁成分与产后黄体功能恢复之间的关系。乳汁成分包括丙酮、乳糖、脂肪、蛋白质、尿素以及脂肪与蛋白质、脂肪与乳糖的比例。用乳汁孕酮浓度来确定从产犊到首次黄体反应（>5 ng/ml）的间隔时间。首次黄体反应的间隔时间分为早期（≤24天）或晚期（>24天）反应两类。与黄体反应延迟的初产和经产奶牛相比，在产后第4周和第5周时观察到早期黄体反应的奶牛体况评分更高。黄体功能早期开始的经产奶牛在第6周至12周时体况评分也更高，而黄体功能早期开始的初产奶牛在第13周至15周时体况评分更高。产后第2周至第4周丙酮水平较高与经产奶牛黄体反应延迟有关。产后第1周、第2周、第3周、第6周、第7周和第8周乳汁乳糖含量较高以及产后第4周脂肪含量较高与经产奶牛早期黄体反应有关。初产奶牛乳汁成分与黄体功能开始之间的关系不如经产奶牛明显，且在产后出现得更晚。产后早期获得的每周乳汁综合指标测量值和体况评分与产后黄体功能恢复密切相关。产后前4周乳汁中的丙酮和乳糖值预测经产奶牛产后黄体功能的敏感性为0.84，特异性为0.86。
