Estradiol-17beta and progesterone in the peripheral blood plasma of goats following superovulation with a single dose of pFSH, hMG or eCG.

During the breeding season, 42 adult German Improved Fawn nanny goats were superovulated with a single dose of pFSH, hMG or eCG at the end or a single application of pFSH 36h before the end of synchronization treatment using flugestone acetate (FGA). Plasma sampling was performed immediately before and 1h after gonadotrophin treatment, twice daily during pre-estrus and estrus and once daily during post-estrus in order to determine peripheral estradiol-17beta and progesterone levels. During that period, ovarian dynamics was followed by serial ultrasound scans (8h interval during pre-estrus and estrus and once daily during post-estrus). Estradiol-17beta profiles differed between the treatment groups exhibiting significantly positive correlations between the mean estradiol-17beta concentrations and the numbers of developing large and medium-sized follicles during estrus. The early bolus application of FSH 36h before the end of synchronization treatment induced an additional advanced estradiol-17beta peak during gestagen dominance. A sharp decrease of estradiol-17beta at the end of estrus seems to play a major role for normal luteal development. Progesterone profiles during the early luteal phase revealed high premature luteal regression. An early progesterone increase was accompanied by low premature regression rates.Although simple B-mode ultrasonography is suitable to follow follicular growth patterns and to determine the ovulation rate following different superovulation regimen endocrinological supervision is required in order to detect a premature corpus luteum insufficiency.