Abstract
Effects were examined on parturition in sows and growth of piglets by the administration of carbetocin (CAR), an oxytocin analogue, after treatment with cloprosterol (CLO), a prostaglandin F2α analogue, at the end of gestation. Experiment 1 was performed to find the optimum CAR dose for improvement of predictability and precision of timing of parturition in sows. Sows were given 0.175mg CLO intramuscularly on day 113 of gestation. Twenty-four hours after CLO administration, sows were given 0.05, 0.1, or 0.2mg CAR, or 25IU oxytocin intramuscularly. The mean interval from CAR injection to birth of the first piglet in sows given 0.1mg CAR was significantly shortened when compared to that in sows given 25IU oxytocin (20min vs 59min, P<0.05). The mean interval from CAR injection to expulsion of the placenta was shortest in sows given 0.1mg CAR. In Experiment 2, sows were given 0.175mg CLO intramuscularly on day 114 of gestation, and the growth of piglets was examined until 14 days after birth. Sows which did not deliver within 24 hours after CLO administration were given 0.1mg CAR or physiological saline solution intramuscularly, and then the influences of CAR administration on the parturition and the growth of piglets were examined. In sows which did not deliver within 24hours after CLO administration, the mean interval from the CAR injection to birth of the first piglet in sows given 0.1mg CAR was significantly shortened when compared to that in sows given physiological saline solution (43min vs 299min, P<0.01). The mean body weights of piglets on day 2, 5 and 14 after birth were not significantly different between the 0.1mg CAR treated group and the saline treated group. These results indicate that daytime parturition in sows can be achieved by administration of 0.1mg CAR after treatment with 0.175mg of CLO.
