Assessment of Reproductive Status of Sika Deer by Fecal Steroid Analysis.

The annual profiles of gonadal steroid hormone secretion in male and female sika deer (Cervus nippon) were examined by means of fecal steroid analysis as a non-invasive method for monitoring the reproductive status. Fecal samples were collected weekly from three female and one male captive deer throughout a year, with more frequent sampling at 1-2 days intervals in the female deer during the breeding season. Fecal samples were dried thoroughly and extracted with diethyl-ether. Progesterone and testosterone concentrations were measured by radioimmunoassays, and expressed as ng per g of dried feces. At the time of each fecal sampling, we observed the reproductive behavior to examine its relevance to the endcrine profile. Fecal progesterone concentrations of female deer represented cyclic changes of 12-13 days intervals during the breeding season which extended from October to January, and the estrous behavior was consistently observed at the nadir of fecal progesterone concentrations. One hind got pregnant following the mating and its fecal progesterone showed a gradual increase to the level which were several times higher as compared with those in the other two non-pregnant hinds. In the buck, on the other hand, there was a clear annual change of fecal testosterone with the peak preceding the onset of ovarian cyclicity in the females. From these results, it is suggested that the reproductive endocrine status of sika deer can be successfully monitored by means of fecal steroid analysis without disturbing the focused animals.