The ovarian condition diagnosed per rectum andits relations to serum concentrations of progesterone and estradiol-17β and prognosis in cows withcystic ovaries

Abstract

The number, size and distribution of follicular cysts (cysts), and coexistence of corpora lutea in 91 dairy cows with cystic ovaries were examined by rectal palpation. Eighty cows were treated with an intramuscular injection of 2040mg of betamethasone or 1020mg of dexamethasone, 9 with 10, 000 MU of HCG with or without simltanious treatment by manual rupture of cysts, and 2 with the manual rupture only. Serum concentrations of progesterone and estadiol-17β were determined by RIA. Relationships between these hormone levels and ovarian conditions as well as prognosis following the treatments were investigated, and results obtained were as follows.
1. Conception rates following the corticoid injection, HCG injection, and manual rupture were 65/80, 7/9 and 2/2, respectively.
2. Cysts were detected in the left ovary of 16 (17.6%) cows, in the right ovary of 35 (38.5%) cows, and in both ovaries of 40 (44.0%) cows. There was no relationship between distribution of cysts and patterns of estrous behavior, as well as conception rates after the treatments.
3. Multiple cysts, more than 3, were found in 11 of 27 (40.7%) cows with nymphomania or continuous estrus, 4 of 31 (12.9%) cows with irregular estrus and 6 of 33 (18.3%) cows with anestrus. No difference was observed in conception rates among the patterns of estrous behavior.
4. Large cysts, more than 3 cm in diameter, were found in 33.3% of cows with nymphomania or continuous estrus, 25.8% of cows with irregular estrus, and 42.4% of cows with nestrus. Considerably higher conception rate was obtained in cows having large cysts as compared with in cows with cysts smaller than 3 cm in diameter.
5. Reciprocal correlation, but not significant, was observed between total volume of cysts which was calculated in each cows from the diameter and number of cysts, and serum concentrations of progesterone and estradiol-17β.
6. Corpora lutea were found in 37 of 91 (40.7%) cows. However, serum concentration of progesterone was not different between cows with coexistent corpora lutea and cows with follicular cysts only. Cows with no corpus luteum showed considerably higher conception rate as compared with that of the others.
7. Manual removal of cysts was tried in 81 cows. All the cysts in 31 (38.3%) cows were ruptured, while no cysts in 33 (40.7%) cows. In remaining 17 (21.0%) cows, some cysts in each cow were ruptured and the others were not. There were no differences in serum concentrations of neither estradiol-17β between the cows whose cysts were all ruptured and those some or all cysts were not ruptured. Conception rate was higher in cows with wholly rupturable cysts than in those with cysts which were unable to rupture.
8. There was no significant correlation between the condition of follicular cysts and the postpartum intervals.
From these findings it may be concluded that there was no obvious correlation between the condition of follicular cysts examined per rectum and serum concentrations of progesterone and estradiol-17β, and that the size of cysts and fragility against the treatment of manual rupture with reference to the prognosis of cystic ovaries. The number of cysts may have a possible relationship to the patterns of estrous behavior.