Smidt W J
Tijdschr Diergeneeskd. 1985 May 1;110(9):361-2.
Samples of milk were taken every sixty minutes in ten cows for a period of ten hours to determine the concentrations of progesterone. The concentrations recorded were related to those in the strippings. All these samples furnished adequately reliable evidence of the presence of an active corpus luteum, with the possible exception of those taken during the last hours prior to milking in some cases.
在十头奶牛身上，每隔六十分钟采集一次牛奶样本，持续十小时，以测定孕酮浓度。记录的浓度与挤奶前的浓度相关。所有这些样本都充分可靠地证明了有活跃黄体的存在，在某些情况下，可能除了在挤奶前最后几小时采集的样本外。
