Plasma oestrone and oestradiol concentrations throughout gestation in cattle: relationship to stage of gestation and fetal number
1999
Patel, O.V. | Takenouchi, N. | Takahashi, T. | Hirako, M. | Sasaki, N. | Domeki, I.
The objectives of the study were to characterise the peripheral plasma oestrone (E1) and oestradiol-17beta (E2) concentrations throughout gestation in the cow and to correlate this with the stage of gestation and fetal number. Cows (n = 10) were equally divided into two groups after non-surgical embryo transfer of in-vitro matured and in-vitro fertilised (IVM-IVF) embryos; Group 1 received a single embryo, Group 2 received twin embryos. Blood was collected about every third day from day 0 (day 0 was defined as first day of standing oestrus), then daily for the last 10 days of gestation and sampling was stopped one day post partum. Plasma E1 concentration exceeded that of E2 throughout gestation in both groups of cows. The time trend concentrations of plasma E1 were significantly affected by the stage of gestation (P < 0(.)01) and fetal number (P < 0(.)01) in the last two trimesters of gestation. The time trend concentrations of plasma E2 were significantly affected by the stage of gestation (P < 0(.)01) but not foetal number (P = 0(.)09). In both groups there was marked preparturient increase in E1 and E2 concentrations. Plasma E2 profile between days 10 prepartum to parturition paralleled E1 in cows carrying a single foetus but was disparate during the same period in the twin-bearing cows. To conclude, our results indicate that although plasma E1 concentration was greater than E2 gestation, both were related to the stage of gestation and that fetal number was correlated with circulating E1 levels in the last two trimesters of gestation.
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