Prepartum changes of plasma concentrations of prostaglandin F and 13,14-dihydro-15-ketoprostaglandin metabolites in pregnant animals exposed to Sarcocystis cruzi or Campylobacter fetus

Pregnant cows at 4- to 5-months' of gestation were exposed to Sarcocystis cruzi or Campylobacter fetus. Plasma prostaglandin F (PGF) and 13,14-dihydro-15-ketoprostaglandin metabolite (PGM) concentrations were determined at intervals from before exposure until abortion or parturition. The plasma PGF concentration of pregnant infected cattle remained at 0.02 +/- 0.04 ng/ml until 24 to 48 hours before abortion or parturition when it increased 5-fold to 0.11 +/- 0.12 ng/ml. The plasma PGM concentration of these cattle remained at 0.10 +/- 0.07 ng/ml until 24 to 48 hours before abortion or parturition when it increased over 10-fold to 1.36 +/- 0.60 ng/ml. This change in PGF and PGM was similar to that of cattle exposed to each of the infective agents and to that of normal cows at parturition. Thus, changes in PGF and PGM concentrations in bovine plasma cannot be used as a diagnostic tool to determine fetal distress or fetal death for these infections.