Ultrasonic survey of follicular development following superovulation with a single application of pFSH, eCG or hMG in goats.

During the breeding season, 42 adult German Improved Fawn nanny goats were superovulated with a single administration of pFSH, hMG or eCG at the end or a single dose of pFSH 36h before the end of estrus synchronization. Development of follicles and corpora lutea were observed by ultrasonic scanning of the ovaries every 8h from gonadotrophin treatment, until the end of estrus and once daily for the following 6 days. Differences in follicular dynamics could be realized in the four superovulation groups, and the duration of the stimulatory action following the single gonadotrophin challenge was estimated to last for 40-72h in the case of pFSH and to exceed 72h in the case of hMG and eCG treatment groups. Corpora lutea could first be detected 3 days after estrus, whereas an exact count was not possible until day 6. The ovulation rates were satisfactory, suggesting that a single injection of pFSH or hMG provides an adequate stimulus to induce a superovulatory reaction. Premature regression of corpora lutea could not be identified ultrasonographically at these early stages of the luteal phase. However, ultrasonography is a suitable method to follow follicular dynamics after superovulation and to estimate the superovulatory response in goats.