Effective Oxytocin Treatment on Placental Expulsion after Foaling in Heavy Draft Mares

摘要

The aim of this study was to establish the effectiveness of administration of oxytocin (OT) oil placental expulsion after foaling. I-our foaling mares with the placentas retained for Lip 1 hr after foaling received OT (50 IU) administration at I fir intervals before expulsion of the placenta. The changes in the plasma concentrations of OT and the PGF2alpha metabolite (PGFM) were investigated, and the influence of OT administration was considered. The results were as follows. The placenta was expelled after one to three OT administrations in all four mares that received OT. In two mares, which expelled the placenta within 30 min after OT administration, the OT concentration increased and remained high. Expulsion or the placenta was delayed in two mares, and one of these mares, which received three doses of OT beginning 1 hr after foaling.. showed only a small increase in the OT concentration after the first administration; the other mare did not receive OT until 3 hr after foaling. The OT concentration was increased before placental expulsion in all the mares, and the PGFM concentration also increased in the two mares with retained placentas. In conclusion, We Suggest that intramuscular administration of 50 IU of OT at 1-hr intervals beginning 1 hr after foaling is effective for inducing placental expulsion.