Monitoring of the Estrous Cycle Using Serum and Fecal Sex Steroid Hormone Metabolites Concentrations and Change of Vaginal Cytology in a Captive Female Hartmann's Mountain Zebra (<i>Equus zebra hartmannae</i>)

Abstract

We assessed serum and fecal sex steroid hormone metabolites concentrations, change of vaginal smear, and rectal temperature measurements in a captive Hartmann's mountain zebra (Equus zebra hartmannae). After serum estradiol-17β concentration peaked, serum progesterone concentration increased. The serum progesterone concentration positively correlated (r = 0.80) with fecal progesterone metabolites concentration two days after blood sampling, indicating that fecal progesterone metabolites concentration reflected serum progesterone concentration well. The dynamics of fecal progesterone metabolites concentration in the zebra showed periodic increases and decreases throughout the year, confirming a mean estrous cycle of 23.1±2.3 days.Furthermore, the percentage of anuclear superficial cells in vaginal smears tended to increase in the non-luteal phase, when fecal progesterone metabolite concentrations were low, but the change was not significant. The rectal temperature showed an increase or decrease during the non-luteal phase, and an increase in the basal body temperature during the luteal phase, which is generally known in humans and other animals, was not confirmed.