Triple blind randomized clinical trials were performed to asses the efficacy of immediate postpartum (pp) injection of prostag landin F, (PGF ), Oxytocin and ergometrine on the duration of placental expulsion following both normal and abnor mal parturitions. One hundred and sixteen Holstein Friesian
and crossbred cows were assigned fandomally following calving to one of four treatment groups. Group I, 32 animals [9 had dystocia (D) and 23 had normal birth (NB)] received saline and used as control. Group 11, 22 cows [4 B and 8 NB), each animal received 25mg PGF [Lutalyse"'), Group III, 40 Cows (5 D and 35 NB), each cow was administered 60 i.u. oxytocin and Group IV, 22 cows (4 D and 18 NB), each cow was given 1.4 mg methylerogometrine. The time until fetal membranes released was calculated. The placenta was consider ed retained, when the fetal membranes were not released 12 hours PP. The rate of placental retention was 34.4% for controls compared to 22.7%, 15% and 31.8% for PGF, oxytoc in and methergine-treated cows respectively. Oxytocin reduced significantly the occurrence of retained placenta, while PGF
caused only rapid release of the placenta when injected immediatly after calving. Moreover, the incidence of PP metritis was less in the treated groups (23.1% vs 34.4% in the controls). In addition, the percentage of animals having optimum service period was significantly greater (x = 23.81, P/ 0.01) in treated groups than in the non treated control group.