Dosage response evaluation of luprostiol administered to pregnant sows

Two trials were completed to investigate the effects of luprostiol in swine. The first trial was to evaluate parturition induced by various dosages of luprostiol compared with those of lutalyse or vehicle. Sows were assigned by random allotment to one of the following treatments on Day 112 of gestation: Group A, control (0 mg luprostiol); Group B (1.88 mg luprostiol); Group C (3.75 mg luprostiol); Group D (7.5 mg luprostiol); Group E (15 mg luprostiol); Group F (10 mg lutalyse). All prostaglandin-treated groups farrowed earlier than the controls (P<0.05), with Groups D (26.3 h), E (31.0 h) and F (25.8 h) having the shortest treatment-to-first-pig intervals, and Groups A (76.0 h), B (54.4 h) and C (40.0 h) having the longest intervals. Luprostiol-treated sows had the shortest farrowing time (P<0.05; range = 3.2 to 3.9 h). Significant differences were found for the time (min) between births: Group A (32.1), Group B (28.4), Group F (35.5) took longer than Group C (20.2), Group D (21.0) and Group E (21.6). In a second trial, 20 crossbred pregnant sows received either vehicle or luprostiol (7.5 mg) on Day 112 of gestation. Progesterone concentrations declined rapidly (P<0.05) in luprotiol treated females but were unchanged in control females during the 24-h collection period. The results of these trials show 7.5 mg luprostiol to be the most effective dose for inducing farrowing.