Sex steroid levels throughout gestation in cows carrying normal and malformed fetuses

Birth of malformed/stillborn calves is a liability to farmers and diagnosis of the condition early in gestation would be of immense economic benefit. We report on peripheral plasma progesterone (P4), estrone (E1) and estradiol (E2) concentrations quantified by radioimmunoassay throughout gestation in twin embryo recipient cows carrying normal (cow N), freemartin(cow F) and schistosomus reflexus fetuses (cow S). The undulating plasma P4 profiles were identical in all three cows throughout gestation apart from that the concentration in cow F dramatically declined on day 254 and it subsequently gave birth to stillborn calves. The plasma E1 concentration progressively increased in cow N to peak at parturition and then rapidly declined a day after parturition. E1 levels were lower in cow F than in cow N and exhibited a sudden increase in concentration at day 254 of gestation followed by a dramatic decline. Cow S had lower E1 levels throughout gestation than cow N and showed an undulating profile. The plasma E2 profile paralleled the plasma E1 profile in all the cows but the E2 concentration throughout gestation was lower than the E1 levels. Plasma E1 and E2 levels declined to < 20 pg/ml in cow N a day after parturition as opposed to > 150 pg/ml E1 and > 20 pg/ml E2 levels, respectively, in cows F and S. Our results indicate that E1 and E2 are better than P4 as prognostic indicators of fetal in-utero status as well as the number of fetuses a cow is gestating.