Concentrations of progestagens and oestrogens in the faeces of pregnant Lipizzan, trotter and thoroughbred mares
Schwarzenberger, F.; Möstl, E.; Bamberg, E.; Pammer, J.; Schmehlik, O.
Journal of Reproduction and Fertility. Supplement 44: 489-499
1991
ISSN/ISBN: 0449-3087 PMID: 1795293 Document Number: 377856
Faecal samples were collected at weekly intervals from pregnant Lipizzan mares during weeks 7-16 following mating and from Lipizzan, Trotter and Thoroughbred mares during the last 3 months of gestation. After parturition, samples were taken daily from the Thoroughbred mares for another 6 days. Non-pregnant mares served as controls. The concns of unconjugated oestrogens (Eg), 20 alpha -OH-progestogens (20 alpha -G) and 20 beta -OH-progestogens (20 beta -G) were measured by enzyme immunoassay. In the faeces of Lipizzan mares, immunoreactive progestogens were significantly elevated above the levels in non-pregnant mares by week 11, and Eg by week 13 of pregnancy onwards. During the last 3 months of gestation, concns of Eg were significantly higher in Trotter mares than in Lipizzan and Thoroughbred mares. Concns of 20 alpha -G and 20 beta -G increased to maximal values in the last month of gestation. There was no significant difference among the 3 breeds with respect to 20 alpha -G but, during the 10 weeks before parturition, concns of 20 beta -G in the Lipizzan mares were significantly lower than those in the Thoroughbred mares. They were also significantly lower than those of the Trotter mares during the last 4 weeks of gestation. After parturition, the concns of Eg and progestogens had declined to baseline values by days 3 and 4, respectively. It was concluded that high concns of progestogens with 20 alpha - and 20 beta -hydroxyl groups are present in the faeces of pregnant mares, especially during the last month of gestation.