Plasma alpha-fetoprotein concentrations in pregnant cows exposed to Sarcocystis cruzi, Campylobacter fetus, or Aspergillus fumigatus.

: Bovine alpha-fetoprotein (AFP) was determined in maternal plasma, using radioimmunoassay in an attempt to detect and monitor fetal distress in pregnant cows. Plasma from pregnant cows in the 4th to 5th month of the gestation which had been exposed to Sarcocystis cruzi, Campylobacter fetus, or Aspergillus fumigatus was used. Plasma AFP concentrations were determined at intervals from before the cows were exposed until they had aborted or calved. The plasma AFP concentration of the exposed pregnant cattle remained at 6.5 +/- 5.0 mg/ml until 24 to 48 hours before abortion or parturition, when the value increased to 25.0 +/- 8.0 ng/ml. This pattern was similar for cattle exposed to each of the infective agents. Unlike in persons, rats, or monkeys, fetal-maternal transfer of AFP seems to be minimal in cows even with inflammation or necrosis of the placentome, Thus, changes in AFP concentrations in bovine plasma cannot be used as a diagnostic tool for fetal distress or fetal death.