Abstract
This experiment was carried out to clarify the practical use of farrowing induction with PGF2$\alpha$ in swine production. Total 320 heads of pregnant sow were used and the effects of administration time, dosage, administration method of PGF2$\alpha$ and parity of sow on the farrowing induction were investigated. The results obtained in this experiment were summarized as following: 1. Total 228 heads out of 240 head which were treated with PGF2$\alpha$ in order to farrow artificially were farrowed normally. the rate of farrowing induction was 95%. 2. Several farrowing symptoms such as restlessness, bloody eye, udder swelling, milk discharge and nest building for piglets were observed in a few minutes after administration of PGF2$\alpha$. 3. Artifical parturition of sow treated with PGF2 at the 113rd, 112nd, 111st, 110th and 109th day of pregnancy were induced 17.0$\pm$7.3, 24.2$\pm$7.0, 31.3$\pm$14.7, 43.0$\pm$12.2 and 62.2$\pm$15.7 hours after administration, and the duration of pregnancy was significantly (P<0.01) shortened by PGF2$\alpha$ anministration. 4. Minimum amount of PGF2$\alpha$ per head for effective farrowing inductin was considered to be more than 5mg, and the more the amount, the shorter time needed for farrowing induction was resulted. 5. Effective farrowing induction was obtained from the sow treated with PGF2$\alpha$ via vulvomucous rather than from the sow treated via intromuscular, and intervals from PGF2$\alpha$ administration to farrowing in 4th-6th farrowed sows were shorter than those of 1st-3rd farrowed sows but no significant difference was observed.