Schiavo J J, Matuszczak R L, Oltenacu E B, Foote R H
J Dairy Sci. 1975 Nov;58(11):1713-6. doi: 10.3168/jds.S0022-0302(75)84773-4.
Milk samples were analyzed for progesterone content by a petroleum ehter extraction and competitive protein binding assay validated for milk. In one experiment, 11 cows were sampled twice daily for 24 days beginning with an observed estrus 15 to 45 days postpartum, and again 19, 21, 23, and 25 days after breeding. Progesterone values during the estrous cycle paralleled those for blood plasma but were slightly higher at estrus (1.49 ng/ml milk) and maximum (9 ng/ml) on days 11 to 16 of the estrous cycle. After breeding, cows later diagnosed pregnant averaged 7.12 ng/ml while those later found to be nonpregnant averaged 2.36 ng/ml. All diagnoses of pregnancy were correct. In a separate experiment there was no difference between milk from front and rear quarters, but progesterone was highest in last milk, intermediate in composite milk, and lowest in first milk.
采用石油醚萃取法和经牛奶验证的竞争性蛋白结合分析法对牛奶样本中的孕酮含量进行分析。在一项实验中，从产后15至45天观察到发情开始，对11头奶牛每天采样两次，持续24天，并在配种后19、21、23和25天再次采样。发情周期中的孕酮值与血浆中的孕酮值相似，但在发情期（牛奶中为1.49纳克/毫升）略高，在发情周期的第11至16天达到最高值（9纳克/毫升）。配种后，后来诊断为怀孕的奶牛平均为7.12纳克/毫升，而后来发现未怀孕的奶牛平均为2.36纳克/毫升。所有怀孕诊断均正确。在另一项实验中，前后乳房的牛奶之间没有差异，但最后挤出的牛奶中孕酮含量最高，混合牛奶次之，首次挤出的牛奶中孕酮含量最低。
