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Johnston, L. A., Donoghue, A. M., O'Brien, S. J., & Wildt, D. E. (1991). Rescue and maturation in vitro of follicular oocytes collected from nondomestic felid species. Biol Reprod, 45(6), 898–906.
Abstract: The potential for rescuing immature oocytes from the ovaries of females of rare felid species which die or undergo medical ovariohysterectomy was evaluated. Ovaries were recovered from 13 species representing 35 individuals in good-to-poor health. Although the majority of females were 10 yr of age or older and in fair-to-poor health, a total of 846 oocytes were recovered of which 608 (71.9%) were classified as fair-to- excellent quality. One hundred of these oocytes were used for initial maturation classification and as parthogenetic controls. Overall, of the 508 fair-to-excellent quality oocytes placed in culture, 164 (32.3%) matured to metaphase II in vitro. For species in which 3 or more individuals yielded oocytes, mean oocyte maturation rates were as follows: 36.2%, tiger; 27.9% leopard; and 8.3%, cheetah. In vitro insemination of oocytes resulted in fertilization (2 polar bodies, 2 pronuclei, or cleavage) rates of 9.1% to 28.6% (leopard) using homologous fresh spermatozoa and 4.0% (lion) to 40.0% (puma) using homologous frozen-thawed spermatozoa. Inseminations using heterologous (domestic cat) spermatozoa also resulted in fertilized oocytes in the tiger, leopard, snow leopard, puma, serval, and Geoffroy's cat (range in fertilization rate, 5.0% for leopard to 46.2% for puma). Cleaved embryos resulted from the insemination of leopard oocytes with homologous sperm (n = 1 embryo) and puma oocytes with domestic cat sperm (n = 3 embryos). These results demonstrate that immature ovarian oocytes from rare felid species can be stimulated to mature in vitro despite an excision-to-culture interval as long as 36 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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Roth, T. L., Armstrong, D. L., Barrie, M. T., & Wildt, D. E. (1997). Seasonal effects on ovarian responsiveness to exogenous gonadotrophins and successful artificial insemination in the snow leopard (Uncia uncia). Reprod Fertil Dev, 9(3), 285–295.
Abstract: Ovaries of the seasonally-breeding snow leopard (Uncia uncia) were examined to determine whether they were responsive to exogenous gonadotrophins throughout the year. The potential of laparoscopic artificial insemination (AI) also was assessed for producing offspring. During the non-breeding, pre-breeding, breeding and post-breeding seasons, females (n = 20) were treated with a standardized, dual- hormone regimen given intramuscularly (600 I.U. of equine chorionic gonadotrophin followed 80-84 h later with 300 I.U. of human chorionic gonadotrophin (hCG)). Laparoscopy was performed 45-50 h after administration of hCG, and all ovarian structures were described. Females with fresh corpora lutea (CL) were inseminated, and anovulatory females were subjected to follicular aspiration to examine oocyte quality. Snow leopards responded to exogenous gonadotrophins throughout the year. Mean number of total ovarian structures (distinct follicles mature in appearance plus CL) did not differ (P > or = 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 of females ovulating was greater (P < 0.05) during the breeding and post-breeding seasons than during the pre-breeding and non- breeding seasons respectively. No Grade-1 quality oocytes were recovered from follicles of anovulatory females. Serum concentrations of oestradiol-17 beta appeared elevated in all females, and neither oestradiol-17 beta concentrations nor progesterone concentrations differed (P > or = 0.05) among seasons. Of 15 females artificially inseminated, the only one that was inseminated in the non-breeding season became pregnant and delivered a single cub. This is the first successful pregnancy resulting from AI in this endangered species.
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