Induction of follicular development in silver foxes (Vulpes vulpes) with equine chorionic gonadotrophin (eCG) and antibodies against eCG.

Experiments were conducted that demonstrated that 1000 iu equine chorionic gonadotrophin (eCG) was effective in induction of follicular development and ovulation in silver foxes during anoestrus. This treatment resulted in large, unovulated follicles; thus, trials in which the effects of eCG were reduced or abrogated by antibodies against eCG were carried out. Passive immunization against eCG on days 3 and 4 after eCG treatment interfered with subsequent follicular development and prevented ovulation. Treatment with eCG antibodies on days 5 or 7 after eCG treatment did not prevent ovulation and neutralization beginning on day 5 appeared to provide for the best ovulatory yield. The results suggest that combinations of eCG and anti-eCG antibody may provide a useful means of inducing ovarian activity in anoestrous foxes.