THE USE OF PROSTAGLANDINS AND OXYTOCIN FOR TRANSCERVICAL RECOVERY OF BOVINE FETUSES AT DAYS 33-58 OF GESTATION

The study of bovine germ cells of known developmental stage calls for alternatives to the recovery of fetuses by surgery or slaughter. Fetus es were therefore obtained during the second month of pregnancy by abo rting 49 animals using a progressively modified treatment regimen of c loprostenol, prostaglandin E(2) (PGE(2)) and oxytocin. The viability o f fetuses was monitored by ultrasonography throughout treatment. Intra cervical treatment with PGE(2) led to cervical dilation in all treated animals. However, retrieval of the fetuses by subsequent flushing of the uterus was successful in only two of six animals. When i.m. inject ions of cloprostenol were given 20-40 h before PGE(2) treatment, fetus es less than or equal to 40 days of gestation were expelled spontaneou sly, while the majority of fetuses greater than or equal to 50 days of gestation were retained. When i.m. injections of oxytocin were given in relation to clinical signs of impending fetal expulsion after clopr ostenol and PGE(2) treatment, 20 of 22 fetuses were expelled 42-53 h a fter the cloprostenol injection. Of these 20 fetuses, 19 were expelled 0-7 h after the cessation of fetal heartbeat. The subsequent fertilit y of animals was not affected. Thus, the final protocol allowed bovine fetuses to be retrieved at predictable times, within a few hours of d eath, with little maternal trauma and without affecting subsequent fer tility.