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

Abstract

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 36 h before the end of estrus synchronization. Development of follicles and corpora lutea were observed by ultrasonic scanning of the ovaries every 8 h 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 40–72 h in the case of pFSH and to exceed 72 h 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.