Treatment of ovarian cyst in swine by intramuscular injection with luteinizing hormone-releasing hormone analogue.

The diagnosis of ovarian cyst was made in 53 anestrous sows, which were treated experimentally with luteinizing hormone-releasing hormone analogue (LH-RH-A). Each sow was injected intramuscularly with 200, 400, or 500 micrograms one to five times. She was examined by rectal palpation in the course of treatment. The blood levels of estrogen and progesterone were estimated in three of the treated sows. From changes in them was followed the process of healing of ovarian cyst. As a result, (1) the interval between the beginning of treatment and the appearance of estrus was 26.9 days on the average, the rate of appearance of estrus 60.4%, that of healing of ovarian cyst 71.6%, that of conception 70.2%, and the number of young of a littler 9.0 on the average. (2) In the three sows subjected to estimation, the blood progesterone concentration increased after injection with LH-RH-A to reach almost the same level as that estimated in the corpus-luteum stage. The time of increase after injection was almost identical with the time when the luteinization of ovarian cyst was found by palpation. In a sow which manifested normal estrus, no ovulation took place, but a cyst was formed in the ovary and the blood estrogen concentration maintained at a high level for 10 days after the beginning of estrus.