CHARACTERIZATION OF ESTROUS CYCLICITY IN THE SABLE ANTELOPE (HIPPOTRAGUS-NIGER) THROUGH FECAL PROGESTAGEN MONITORING

Fecal progesterone metabolite monitoring techniques were validated for the sable antelope and used to characterize ovarian cycle dynamics an d reproductive seasonality in a captive population at the National Zoo logical Park's Conservation and Research Center. Hormone was homogeneo usly distributed within fecal samples. Longitudinal fluctuations in fe cal progesterone metabolites were consistent with typical luteal phase patterns and corresponded closely with changes in serum progesterone. The las time from an im injection of progesterone to peak excretion i n feces was 16 h. The pattern of births showed a slight peak in the su mmer (May-July), but year-round endocrine monitoring of six nonpregnan t females showed no evidence of seasonality in ovarian activity. Femal es exhibited 11-14 estrous cycles per year, averaging 24.2 +/- 0.9 day s in length. Luteal and interluteal phases were 18.4 +/- 0.9 and 5.8 /- 0.4 days in length, respectively Although only a small number of hi ppotragine antelope species have been studied, data indicate that they exhibit considerable interspecific variability in estrous cycle lengt h and reproductive seasonality and thus may be a useful group for furt her investigation of factors regulating fertility. (C) 1998 Academic P ress.