Patterns of excretion of fecal estradiol and progesterone and urinary chorionic gonadotropin in Grevy’s zebras (Equus grevyi): Ovulatory cycles and pregnancy

Abstract

The ovulatory cycle and pregnancy of the endangered Grevy's zebra (Equus grevyi) was characterized by analyzing excretion patterns of fecal estradiol and progesterone. Pregnancy was further described by assay of urinary equine chorionic gonadotropin. Courtship and mating behavior were similar to that seen in the domestic horse, but cycle length was longer, ranging from 28 to 35 days. Steroid hormone profiles during pregnancy were likewise similar to the horse, but gestation length was longer (391 and 406 days) in the two mature mares. A young mare was first seen to mate when 1 year 3 months of age, at which time she conceived but then aborted at 101 days' gestation. Conception occurred after one and possibly two more abortions. A healthy foal was born after a gestation period of 425 days, when the mare was 3 years 4 months old, the youngest age at first foaling to be reported for this species. Equine chorionic gonadotropin (eCG) was first detected between 35 and 40 days' gestation, as in the horse, returning to baseline at about 195 days. However, in one young mare, eCG was also detectable around the time of ovulation. The eCG antibody may have crossreacted with luteinizing hormone, which would have been reaching peak concentrations at about that time. The general agreement of the endocrine results with observed occurrence of mating behavior and of parturition demonstrates that assay of excreted hormones can be used to document puberty, monitor ovarian cycles, and diagnose and monitor pregnancy in Grevy's zebra mares. Zoo

Identification of Fecal Sex Steroid Metabolites and Evaluation of Ovarian Cycle and Pregnancy in Somali Wild Ass (Equus africanus somaliensis)

“…It has been reported that measuring fecal progestagens can be used for monitoring the estrous cycle in the domestic horse [15][16][17], Przewalski's horse [10] and Grevy's zebra [11]. In our study, the change in fecal progestagens showed ovarian cyclicity and was an average of 22.…”

A review of the reproductive biology and breeding management of tapirs

“…Fecal progestagen analyses are used to assess luteal activity in many Perissodactyla species, such as the domestic horse (Schwarzenberger et al 1996a;Palme et al 2001), the zebra (Asa et al 2001) and several rhinoceros species (Schwarzenberger et al 1996b(Schwarzenberger et al , 2000Berkeley et al 1997;Heistermann et al 1998;Patton et al 1999;Brown et al 2001) and would be invaluable for tapirs. However, evaluations thus far have failed to yield data that are biologically relevant, or correlate with serum profiles (A. Rubiano et al, unpubl.…”

Fundamental Studies of the Reproductive Biology of the Endangered Persian Onager (Equus hemionus onager) Result in First Wild Equid Offspring from Artificial Insemination1

“…There are seven extant species in the Equidae family [1] and only a few published reproductive studies, including those for the Grévy's zebra (Equus grevyi) [2], mountain zebra (Equus zebra) [3,4], plains zebra (Equus burchellii) [5,6], and Przewalski's horse (Equus ferus przewalski) [7][8][9]. The reproductive physiology of wild asses (three species; eight subspecies [10]) has been largely ignored.…”