Reproductive hormone and ovarian changes in cows with ovarian cysts.

Changes in ovaries and concentrations of reproductive hormones were monitored for 30 days in eight dairy cows with ovarian cysts. Diagnosis of ovarian cysts was based upon detection of single or multiple follicular structures on one or both ovaries of at least 2.5 cm in diameter twice at 10 days apart. Eleven days following the initial diagnosis (day 0) cows were bled at .5-h intervals for 4 h. Beginning the next day eight blood samples were collected from each cow at 4-day intervals. Ovarian examinations were subsequent to blood collection on days 1 to 29. Although concentrations of luteinizing hormone in plasma were variable within cows, only four cows had maximum concentrations greater than 3.0 ng/ml at any time. During the 29 day interval concentrations of progesterone and estradiol-17 beta were not only different among cows but also variable within cows. Over the 29 days, only one cow had mean concentrations of progesterone in plasma greater than 1.0 ng/ml, but concentrations were 1.0 ng/ml or greater in seven of the cows in at least one of the eight plasma samples. Ovarian cycles were not reestablished in any of the cows. However, cystic structures regressed in six cows but only in conjunction with the formation of new ovarian cysts.