Abstract
The concentration of oestrone sulphate in whey obtained from 66 pregnant dairy goats was measured by direct radioimmunoassay. The mean time at which pregnancy was first detected was day 41 of gestation. Levels remained low (37 pmol/l–0·96 nmol/l, mean = 167 pmol/l) until week 5 of gestation when they rose rapidly. The test had an accuracy of 95·6%, was able to distinguish true from pseudopregnancy, and suggested that pregnancy in females carrying multiple fetuses could be detected earlier, possibly as a result of the fetal-placental origin of oestrone sulphate. J. Endocr. (1986) 110, 133–136