title: Detection of pregnancy by radioimmunoassay of a novel pregnancy-specific protein in serum of cows and a profile of serum concentrations during gestation.
abstract: The development of a double antibody radioimmunoassay for a bovine pregnancy-specific protein (pregnancy-specific protein B; PSPB) is presented. By means of this assay, PSPB could be measured in serum of pregnant cows. Five dairy cows were bled throughout gestation to measure serum levels of PSPB. Serum concentrations (means +/- SE) exceeded 1 ng/ml by 30 days postbreeding and increased gradually through three months (9 +/- 0.6 ng/ml), six months (35 +/- 6 ng/ml), and nine months (150 +/- 75 ng/ml) of gestation. Maximum levels of PSPB (542 +/- 144 ng/ml) were reached two days before parturition and then steadily declined to less than 78 ng/ml by 21 days postpartum. In 21 cows bled daily from 15 through 30 days postbreeding, PSPB could be measured in a few cows before and in most cows by 24 days after breeding. In a commercial herd of 102 beef cows, the assay could detect pregnancy earlier and more accurately than the routine method of rectal palpation. This radioimmunoassay measures a unique antigen that, for the first time, provides a serological method for detecting pregnancy in cows.
mesh_terms: D000818:Animals; D002417:Cattle; D019411:Clinical Laboratory Techniques; D003429:Cross Reactions; D005260:Female; D007106:Immune Sera; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood*; D011270:Pregnancy, Animal / Q000097:blood*; D011863:Radioimmunoassay / Q000379:methods
chemical_list: D007106:Immune Sera; D011257:Pregnancy Proteins