The aim of the present study was the confirmation of pregnancy diagnosis in mares by the determination of oestradiol-17 b in faeces. The research was carried out on 30 cyclic mares. Faeces samples were collected through pregnancy at monthly intervals. The faeces samples of pregnant and non-pregnant mares contained a mean oestradiol-17 b concentration of 9.39 ± 2.63 and 7.70 ± 2.00 ng/g, respectively in the 4th month of gestation. From the 5th month of pregnancy the oestradiol-17 b concentration in pregnant mares was significantly higher than in non-pregnant mares. Oestradiol-17 b levels were estimated to be 71.20 ± 8.00 and 4.60 ± 2.20 ng/g in pregnant and non-pregnant mares in the 5th month of pregnancy, respectively. However, the confirmation of pregnancy with the enzyme - immunoassay technique was possible after the 5th month of gestation; faeces samples collected at short intervals would be necessary to obtain a reliable pregnancy diagnosis.

The aim of the present study was the confirmation of pregnancy diagnosis in mares by the determination of oestradiol-17 b in faeces. The research was carried out on 30 cyclic mares. Faeces samples were collected through pregnancy at monthly intervals. The faeces samples of pregnant and non-pregnant mares contained a mean oestradiol-17 b concentration of 9.39 ± 2.63 and 7.70 ± 2.00 ng/g, respectively in the 4th month of gestation. From the 5th month of pregnancy the oestradiol-17 b concentration in pregnant mares was significantly higher than in non-pregnant mares. Oestradiol-17 b levels were estimated to be 71.20 ± 8.00 and 4.60 ± 2.20 ng/g in pregnant and non-pregnant mares in the 5th month of pregnancy, respectively. However, the confirmation of pregnancy with the enzyme - immunoassay technique was possible after the 5th month of gestation; faeces samples collected at short intervals would be necessary to obtain a reliable pregnancy diagnosis.