摘要：The present study aimed to estimate the ovulation time in the mare on the basis of changes in urinary estrone sulphate (E1S) concentrations by using an EIA kit, originally used for plasma. Urine samples were collected from mares during the preovulatory period until ovulation. The urinary E1S concentrations showed a gradual increase from 153 ± 45 ng/ml urine and 210 ± 22 ng/mg creatinine (Cr) at D-5 and then reached a peak of 316 ± 43 ng/ml urine and 394 ± 35 ng/mgCr at D-2 in 81% of the mares in both groups. These findings indicate that daily determination of urinary E1S concentrations allows us to estimate the ovulation day and subsequently decide the optimum mating service time in mares.
