PREGNANCY AND OVULATION DETECTION IN BISON (BISON BISON) ASSESSED BY MEANS OF URINARY AND FECAL STEROIDS

Sexually mature bison (Bison bison) cows were tested for both pregnancy and ovulation by means of urinary steroid metabolites and fecal steroids. The accuracy of pregnancy diagnosis was determined among 18 bison cows, in approximately the third month of gestation, by means of urinary pregnanediol-3δ-glucuronide (PdG), urinary estrone conjugates (E₁C), and fecal total estrogens (TE). Urinary PdG was 100% accurate, urinary E₁C was 89% accurate, and fecal TE was 100% accurate in predicting pregnancy. Fecal progesterone (P₄) and TE, as well as urinary E₁C and PdG concentrations all increased from conception (August) through January, but significant differences were not apparent until November. During the rutting season ovulation was detected by increases in either urinary PdG or fecal P₄ concentrations. Both pregnancy and ovulation were detected in uncaptured bison with reasonable accuracy by means of urinary and fecal steroids or their metabolites.