Pregnancy-associated glycoprotein levels in cattle exhibiting prolonged pregnancy: case reports.

Prolonged gestation (PG) is a complex clinical entity which occurs in bovine species. This pathology has been described in Belgian Blue cattle. PG may require termination by cesarean section. Fetuses often exhibit increased body weight, long hair and well erupted teeth. All calves die within minutes or hours after birth. From endocrinological point of view, PG is highly correlated to fetal adenohypophyseal aplasia.
The aim of the present study was to investigate the usefulness of PAG RIA for diagnosis of prolonged gestation in Belgian Blue cattle.
Blood samples were collected from five Blue Belgian cows having an abnormally long pregnancy length (10 to 15 months). PAG was measured by routine RIA with the use of antiserum AS497 as primary antibody. A purified bovine PAG preparation (boPAG67kDa) was used as standard (0.8 to 100 ng/mL) and for radio-iodination (125I). Cesarean section was used for termination of pregnancy of those cows exhibiting abnormal PAG concentrations. Morphological aspect and viability of fetuses were reported.
Concentrations of PAG were very low (94.1 ng/mL, 50 ng/mL, 5 ng/mL, 110 ng/mL and 26 ng/mL) in the five females suffering of prolonged gestation. Fetuses issued from prolonged gestation exhibited long hair, well erupted teeth and died within few minutes after birth.
In conclusion, PAG concentration is a good indicator of prolonged gestation in cattle. Concentrations are much lower than those expected in normal ongoing pregnancy (<120 ng/mL versus >1,000 ng/mL).