Ultrasonographic appearance of the conceptus, fetal heart rate and profiles of pregnancy-associated glycoproteins (PAG) and prostaglandin F2α-metabolite (PGF2α-metabolite) after induction of fetal death with aglepristone during early gestation in cattle

Control heifers produced healthy calves at term, but in treated heifers, FD occurred on average at 58 (range 48-80) h after first injection of aglepristone. Fetal death was always preceded by a visible reduction of the amount of allantoic fluid and by segregation of the allantochorionic membrane from the endometrium. FHR remained rather constant in both groups, but a (non-significant) drop in FHR around 8 h before FD was diagnosed in four of five treated animals. All fetuses were expulsed after FD. Levels of PAG remained constant or even slightly increased in controls, but decreased in treated animals from T2 onward: levels during T4 and T5 significantly differed from those during T1 and from values in controls during T4 and T5 (P < 0.01). PGF2α-metabolite levels did not change in the controls, but in the treated group they were significantly higher during T3 when compared to T1 (P < 0.05). After this increase, a sharp decrease in PGF2α-metabolite level occurred, reaching a significantly lower level at T5 when compared to control animals (P = 0.01). It is concluded, that FD induced by aglepristone is preceded by ultrasonographic visible changes in fetal membranes and fluids and a rise in PGF2α-metabolite and is followed by a drop in PAG and PGF2α-metabolite.