Seasonal effects on ovarian responsiveness to exogenous gonadotrophins and successful artificial insemination in the snow leopard (Uncia uncia)

Abstract

Ovaries of the seasonally-breeding snow leopard(Uncia uncia) were examined to determine whether theywere responsive to exogenous gonadotrophins throughout the year. The potentialof laparoscopic artificial insemination (AI) also was assessed for producingoffspring. During the non-breeding, pre-breeding, breeding and post-breedingseasons, females (n = 20) were treated with astandardized, dual-hormone regimen given intramuscularly (600 I.U. of equinechorionic gonadotrophin followed 80-84 h later with 300 I.U. of humanchorionic gonadotrophin (hCG)). Laparoscopy was performed 45-50 h afteradministration of hCG, and all ovarian structures were described. Females withfresh corpora lutea (CL) were inseminated, and anovulatory females weresubjected to follicular aspiration to examine oocyte quality. Snow leopardsresponded to exogenous gonadotrophins throughout the year. Mean number oftotal ovarian structures (distinct follicles mature in appearance plus CL) didnot differ (P ≥ 0 · 05) with season, but the proportion of CL :total ovarian structures was greater (P < 0 ·01) for the breeding season compared with all other seasons. The proportion offemales ovulating was greater (P<0 · 05)during the breeding and post-breeding seasons than during the pre-breeding andnon-breeding seasons respectively. No Grade-1 quality oocytes were recoveredfrom follicles of anovulatory females. Serum concentrations of oestradiol-17bappeared elevated in all females, and neither oestradiol-17βconcentrations nor progesterone concentrations differed(P ≥ 0 · 05) among seasons. Of 15 femalesartificially inseminated, the only one that was inseminated in thenon-breeding season became pregnant and delivered a single cub. This is thefirst successful pregnancy resulting from AI in this endangered species.