[Results of experimental studies to control birth in swine]

An experiment was applied to ovulation-synchronised gilts and old sows. Mean values of pregnancy time were almost one and the same. Variations between the 111th and 117th days were exhibited within the control group. The test animals, however, farrowed on the 109th, 110th, and 111th days within spans of three days (113th to 115th day of pregnancy), following intramuscular injection of 75 mg DXMS. Intramuscular injection of 5 mg prostaglandin F2alpha on the 112th day of pregnancy triggered parturition within 25-36 hours in ten of 13 treated sows, whereas 19 of 20 sows gave birth within 27.7 +/- 5.1 hours in response to injection of 7.5 mg PGF2alpha.