EFFECT OF INTRACERVICAL ADMINISTRATION OF A PROSTAGLANDIN-E(2) GEL INPREGNANT AND NONPREGNANT HEIFERS

The effects of prostaglandin E2 (PGE2) on cervical opening in non-preg nant and pregnant heifers was studied, and in the pregnant animals the effect on the embryo was studied by means of ultrasonography. In four consecutive experiments, 5 ml of saline, a gel containing 2 mg or 6 M g PGE2 was administered intracervically to four non-pregnant heifers, and 2 mg of PGE2 was administered to heifers pregnant 33 to 40 days. A ll the groups treated with PGE2 experienced an increase in the concent rations of prostaglandin metabolite in plasma (P<0.05) shortly after a dministration, which reached a peak 15 to 30 minutes after administrat ion. An increase in cervical opening was evident in all the PGE2-treat ed heifers (P<0.05) from three hours after treatment. There was no dif ference between the effect of the two doses. The heifers which receive d saline did not show any significant changes. In addition, the treate d heifers showed cervical softening, congestion and mucus secretion wh ich were more pronounced in the pregnant heifers. The embryos were not affected. Plasma progesterone concentrations remained unchanged in al l the experiments.