Monitoring ovarian function in scimitar-horned oryx (Oryx dammah) by measurement of fecal 20α-progestagen metabolites
Publication Type: |
Journal Article |
Year of Publication: |
1995 |
Authors: |
H. J. Shaw, D. I. Green, A. W. Sainsbury, W. V. Holt |
Publication/Journal: |
Zoo Biology |
Publisher: |
A Wiley Company, Inc., Wiley Subscription Services |
Keywords: |
ovarian cycle, ovulation, reproductive assessment |
ISBN: |
1098-2361 |
Abstract:
Abstract 10.1002/zoo.1430140305.abs The feasibility of monitoring ovarian function in scimitar-horned oryx (Oryx dammah) by measurement of fecal 20α-progestagens was investigated. Fecal samples were collected daily or on alternate days over a 4–11 month period from five oryx during natural (n = 4) or synthetic PGF2α (cloprostenol)-controlled (n = 1) cycles. Of the four oryx undergoing natural cycles, three had regular access to a vasectomised male, and mating dates were recorded. Ultrasonography was used to monitor changes in reproductive tract morphology in the female administered with cloprostenol. Neutral steroids were extracted from feces with methanol:petroleum ether (2:1 v/v) after first removing phenolic steroids with potassium hydroxide (1 M). The concentration of 20α-progestagens in the methanol phase was measured by enzymeimmunoassay. Excretion of 20α-progestagens in all females followed a cyclic pattern corresponding to the follicular and luteal phases of the ovarian cycle. Concentrations of fecal 20α-progestagens were on average twentyfold greater during the luteal phase compared with the follicular phase. Mean (±SD) ovarian cycle length, based on fecal progestagen profiles, was 24.4 ± 2.2 days with mean (±SD) luteal and follicular phase lengths of 18.7 ± 2.8 and 5.7 ± 1.6 days, respectively. Mating by a vasectomized male occurred when 20α-progestagen concentrations were still elevated or declining. Similarly, fecal progestagens did not return to follicular phase concentrations for 4–5 days after administration of cloprostenol, and a 4 day delay was observed between ovulation, as visualized by ultrasound scanning, and a rise in fecal 20α-progestagens. These data suggest a time lag of approximately 4 days between reproductive events and changes in fecal 20α-progestagen concentrations. We conclude that measurement of immunoreactive 20α-progestagen concentrations in feces has limited application for predicting ovulation or accurately timing inseminations because of delay in steroid excretion, but will enable noninvasive monitoring of ovarian cycles in scimitar-horned oryx for fertility assessment and for determining the outcome of artificial insemination programs. © 1995 Wiley-Liss, Inc.