EFFECTS OF EXOGENOUS PROSTAGLANDIN-F2-ALPHA (PGF2-ALPHA) ON PREGNANCYSTATUS IN WHITE-TAILED DEER

As part of a study to develop contraceptive methods for white-tailed d eer (Odocoileus virginianus), it was necessary to terminate pregnancie s in some does. The abortifacient chosen was PGF2alpha. At 76 days or less of gestation, PGF2alpha administration (10 mg i.m.) did not decre ase mean serum progesterone (P) concentrations, and only one doe of 13 aborted. Re-administration of PGF2alpha (15 mg i.m.) on approximately day 97 of gestation (21 days after the first injection) did not alter mean serum P concentrations 6 days postinjection, and only one doe of 11 aborted. A third injection of PGF2alpha (25 mg i.v.) on approximat ely day 113 of gestation (16 days after the second injection) tended t o decrease mean P concentrations by 1.4 ng/ml 2 days following treatme nt, and no doe of 11 aborted. A fourth injection of PGF2alpha (50 mg i .m.) on approximately day 124 of gestation (11 days after the third in jection) decreased mean P concentrations by 2.9 ng/ml 2 days following treatment (P < 0.05), and two of 11 does aborted. Finally, a combinat ion of 50 mg PGF2alpha and 15 mg betamethasone was administered i.m. t o the remaining pregnant does on approximately day 140 of gestation (1 6 days after the fourth injection). Mean serum P concentrations decrea sed from 4.8 +/- 0.4 ng/ml to 0.7 +/- 0.2 ng/ml 3 days postinjection, a mean decrease of 4.1 ng/ml (P < 0.05). This treatment induced aborti on in five of seven does. These data suggest that PGF2alpha alone, at a dose that causes luteolysis and pregnancy termination in cows and go ats, does not do so in pregnant white-tailed deer. However, a combinat ion of betamethasone and PGF2alpha may prove to be an effective luteol ytic agent or abortifacient for white-tailed deer. (c) Wiley-Liss, Inc .