Circumventing the natural, frequent oestrogen waves of the female cheetah (Acinonyx jubatus) using oral progestin (Altrenogest)

Abstract

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 ~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.

Public exposure and number of conspecifics have no influence on ovarian and adrenal activity in the cheetah (Acinonyx jubatus)

“…There are other oddities, including that females normally produce rather 'abrupt' waves of estrogenic activity every 5 to 30 days, with most peaks being unaccompanied by sexual behavior (Brown et al, 1996;Crosier et al, 2016;Wielebnowski and Brown, 1998). Cheetahs also inexplicably produce periods of complete reproductive inactivity for as long as 2 to 5 months before randomly re-initiating estrogen cyclicity (Brown et al, 1996;Crosier et al, 2016). These intervals of ovarian shutdown, or anestrus, are not synchronous among females and are unrelated to seasonality (Brown et al, 1996).…”

“…There are multiple reports on the independent monitoring of ovarian (Adachi et al, 2011;Brown et al, 1996;Wielebnowski et al, 2002) or adrenal (Crosier et al, 2016;Koester et al, 2015;Terio et al, 2004;Wells et al, 2004) hormone metabolite patterns in the feces of captive-held cheetahs. However, there has been little emphasis on the simultaneous assessment of both metabolites in adult females, especially to determine if measured glucocorticoids are related to estrogen profiles or affect ovarian activity.…”

Morphology of the Uterotubal Junction of the Cheetah (Acinonyx jubatus)

“…These cycles occur year round with estrogen peaks occurring on average every 9.9 ± 2.2 days, with older females displaying shorter intervals (Crosier et al, ). However, these active, short bursts of estrogenic activity are interrupted in most captive cheetah by significant periods of ovarian acyclicity, the majority of which occur during winter or spring (Crosier et al, ). The reproductive tracts of the seven cheetahs examined contained no evidence of pregnancy or recent ovulations.…”

“…The chance of this synchronized low estrogen picture occurring among the six group housed cheetahs is unlikely if they were actively cycling as it would be expected that some cheetahs would be in proestrus and estrus, with associated larger follicles (4–6 mm) (Schulman et al, ) and signs of estrogenization in the uterus. Additionally, the South African cheetah died during autumn and the Namibian cheetahs were euthanized mid‐winter when acyclicity is most prevalent (Crosier et al, ). Based on all of the above factors, we conclude that the cheetahs are more likely to be in anestrus than interestrus.…”

Getting the world’s fastest cat to breed with speed

“…Females housed together can suppress ovulation unless the cats know and like each other. And despite their frequent cycles, females show few outward signs of estrus unless they're interested in mating with a male (12).…”