Estradiol and progesterone metabolite concentration in white-tailed deer (Odocoileus virginianus) feces

Assays of reproductive hormone metabolites require validation in each animal species. For validation of methodology in white-tailed deer (Odocoileus virginianus), fecal samples were collected from females that had been injected by blowgun with estradiol, progesterone, or a control substance. Analysis by radioimmunoassay revealed that estradiol and pregnanediol were more abundant fecal metabolites of estrogens and progestins than were estrone or progesterone. Peak excretion rates of estradiol and pregnanediol occurred within 12 and 24 hr of injection, respectively. Ovulation time was estimated by measuring the frequency of occurrence of eight behavior patterns, including copulation. Profiles were compiled for three deer over the course of estrus and early pregnancy for estradiol, estrone, progesterone, and pregnanediol using radioimmunoassay. Pregnanediol was excreted at concentrations about 1,000 times higher than those of the other three fecal steroid metabolites, and pregnanediol differed in concentration during estrus, the luteal phase, and early pregnancy. Consequently, a simpler enzyme immunoassay was adapted and used to measure pregnanediol levels over the course of estrus and early pregnancy for seven deer. Measurement of fecal pregnanediol is useful for monitoring reproductive events in female white-tailed deer.