Crosier, Adrienne E., Comizzoli, Pierre, Koester, Diana C., and Wildt, David E. 2017. "Circumventing the natural, frequent oestrogen waves of the female cheetah (Acinonyx jubatus) using oral progestin (Altrenogest)." Reproduction Fertility and Development 29 (8):1486-1498. https://doi.org/10.1071/RD16007
Cheetah are induced ovulators, experiencing short, variable oestrogen waves year-round. Exogenous gonadotrophin administration induces ovulation, but success is variable and often improves if ovaries are quiescent. After affirming the presence of short-term oestrogenic waves, we examined the effect of the timing of administration of exogenous equine and human chorionic gonadotrophins (eCG-hCG) within the oestrogen concentration pattern on subsequent follicle development and oocyte and corpus luteum quality. We also investigated ovarian suppression using an oral progestin (Altrenogest, 7 days) and assessed whether Altrenogest moderated adrenal activity by reducing glucocorticoid metabolites. All cheetahs exhibited short (every,similar to 7-10 days), sporadic, year-round increases in faecal oestradiol punctuated by unpredictable periods (4-10 weeks) of baseline oestradiol (anoestrous). Gonadotrophin (eCG-hCG) efficacy was not affected by oestradiol ` wave' pattern if administered >= 3 days after an oestrogen peak. Such cheetahs produced normative faecal progestagen patterns and higher numbers (P<0.06) of mature oocytes than females given gonadotrophins <= 2 days after an oestradiol peak. Altrenogest supplementation expanded the interval between oestradiol peaks to 12.9 days compared with 7.3 days without progestin pretreatment. Altrenogest-fed females excreted less (P<0.05) glucocorticoid metabolites than non-supplemented counterparts. Results show that Altrenogest is effective for suppressing follicular activity, may contribute to reduced glucocorticoid production and may result in more effective ovulation induction via gonadotrophin therapy.