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

Abstract

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 36 h before the end of synchronization treatment using flugestone acetate (FGA). Plasma sampling was performed immediately before and 1 h after gonadotrophin treatment, twice daily during pre-estrus and estrus and once daily during post-estrus in order to determine peripheral estradiol-17β and progesterone levels. During that period, ovarian dynamics was followed by serial ultrasound scans (8 h interval during pre-estrus and estrus and once daily during post-estrus). Estradiol-17β profiles differed between the treatment groups exhibiting significantly positive correlations between the mean estradiol-17β concentrations and the numbers of developing large and medium-sized follicles during estrus. The early bolus application of FSH 36 h before the end of synchronization treatment induced an additional advanced estradiol-17β peak during gestagen dominance. A sharp decrease of estradiol-17β 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.