Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Evidence for prostaglandin involvement in early luteal regression of the superovulated nanny goat (Capra hircus).

Abstract

Feral ♀ goats of various ages were treated with intravaginal progestogen sponges for 16 days to synchronize oestrus. On day 2 before sponge removal, the goats were given 1200 IU PMSG to induce superovulation; 6 of the goats were also injected every 12 h with flunixin meglumine, a PG synthetase inhibitor, from days 3 to 7 of the synchronized oestrous cycle. Jugular blood samples were collected from all ♀♀ into heparinised syringes at daily intervals over the 2 days before sponge removal, twice daily for the next 2 days, then at hourly intervals from 09.00 to 17.00 h for 2 days and then twice daily for a further 2 days, for measurement of the plasma concentrations of progesterone and the PGF metabolite 13,14-dihydro-15-keto-PGF (PGFM) by radioimmunoassay. Intermittent surges in plasma PGFM concentration were observed in hourly samples collected from all 4 untreated ♀♀ but in only 2 of the 6 inhibitor-treated ♀♀ (P<0.05), and the peak plasma PGFM concentration was reduced in these 2 inhibitor-treated goats compared with the control goats. The corpora lutea of the inhibitor-treated ♀♀ appeared to be functional, as indicated by the plasma progesterone profile and endoscopic examination of the corpora lutea. In the control ♀♀, however, there was evidence of premature regression of corpora lutea. These results suggest that the premature release of PGF may be the cause of premature regression of corpora lutea in ♀ goats induced to superovulate.