Ovarian sensitivity to exogenous gonadotropins was assessed in the cheetah (Acinonyx jubatus) and clouded leopard (Neofelis nebulosa) to help optimize artificial insemination (AI). Eighteen female cheetahs were used on 29 occasions and were given i.m. injections of 100, 200, or 400 IU eCG and 100 or 250 IU hCG 80 h later. Twenty-three female clouded leopards were treated i.m. on 27 occasions with 25, 50, 75, 100, 200, or 400 IU eCG followed 80 h later with 75, 140, or 280 IU hCG. Ovaries were examined laparoscopically at 43-48 h after hCG in cheetahs and 39-50 h in clouded leopards. All gonadotropin dosages stimulated ovarian activity in both species, but ovulation success and corpus luteum (CL) morphology varied (p < 0.05) with treatment. For both species, the highest and intermediate eCG dosages resulted in ovulation in a high proportion (72-100%) of females. The lowest eCG dosage, although capable of stimulating follicular development, compromised ovulation and resulted in few (< 26%) postovulatory females. For each species, small CL (2-4-mm diameter) were observed with the highest and lowest eCG dosage, and large CL (5-8-mm diameter) were associated with intermediate eCG dosages. Aged CL (10-12 mm diameter) were observed in 4 of 23 (17.4%) clouded leopards with no prior male exposure, indicating occasional spontaneous ovulation. Nineteen laparoscopic intrauterine AI procedures were performed in eCG/hCG-treated postovulatory cheetahs. Eighteen AI procedures were conducted in eCG/hCG-treated postovulatory clouded leopards. Six of the 13 cheetahs (46%), all in the 200-IU eCG/100-IU hCG group, became pregnant, in contrast to none of the clouded leopards. This study has revealed differences in ovarian activity in two wild felid species as a result of changes in exogenous gonadotropin dosage. Because of this dose-effect response, this comparative approach is necessary to identify a gonadotropin regimen that can mimic "normalcy." Even then, the relatively high AI success in the cheetah compared to the clouded leopard suggests that factors other than ovarian response can dictate the efficiency of assisted reproduction in this taxon.

The clouded leopard (Neofelis nebulosa) is an endangered species difficult to propagate in captivity because of sexual incompatibility between paired individuals. Fecal estradiol (E2) and progesterone (P4) metabolites were quantified in 14 females to noninvasively monitor seasonal reproductive patterns and compare ovarian responses to natural mating vs. exogenous gonadotropins. Increased E2 excretion was associated with behavioral estrus or eCG treatment, whereas elevated P4 metabolites were observed during natural and hCG-induced pregnant and nonpregnant luteal phases. On the basis of fecal E2 profiles, duration of the estrous cycle was 24 +/- 2 days, with estrus lasting 6 +/- 1 days. Mean gestation length was 89 +/- 2 days, whereas duration of the nonpregnant luteal phase was 47 +/- 2 days. Females experienced a seasonal anestrus during the late summer and early fall. One female demonstrated a lactational anestrus after the birth of three cubs. On nine occasions, clouded leopards ovulated spontaneously (based on elevated fecal P4 metabolite concentrations) in the absence of mating. Patterns of eCG-stimulated E2 excretion were similar to those associated with natural estrus and were unaffected by eCG dosage (25, 50, or 100 IU). In contrast, post-hCG P4 metabolite profiles varied considerably, with responses including anovulation, attenuated luteal P4 metabolite production, and hyperstimulated luteal function. In some females, compromised luteal function after ovulation induction appeared to be due to the presence of mature CL from previous spontaneous (without copulation) ovulations at the time of gonadotropin treatment. Duration of post-hCG P4 metabolite excretion was reduced approximately 40% in these individuals compared to females with no evidence of active luteal activity. In sum, these are the first data describing the ovarian cycle of this endangered species. The information is important because it is based on the longitudinal assessment of multiple females using a completely atraumatic approach, thereby eliminating the potential confounding impact of stress. Data indicate that spontaneous ovulations and the presence of active luteal tissue on the ovary can profoundly affect ovarian responses to exogenous gonadotropin therapy. Therefore, fecal steroid monitoring can serve as a useful adjunct to developing assisted reproduction techniques, especially the hormonal induction of ovulation for planned artificial insemination.