In an experiment 575 sows were inseminated by heterospermic insemination doses from 6 pairs of boars. Each sow from the experimental group was inseminated in oestrus and reinseminated with insemination doses from one of the 6 homology pairs of boars. The dispermic insemination doses used for heterospermy contained 4.77 +/- 1.62 X 10(9) biologically active sperm cells. The control group of sows was inseminated by sc, called non-genuine heterospermy, i.e. by homospermic insemination doses with reinsemination by the dose from another boar with the content of sperm cells in the span of the experimental doses. We did not find a significant difference (P < 0.05) in the farrowing rate after the first insemination between the individual groups of boars but there is a significant difference between the experimental and control group of sows (66.51% vers. 60.54%; P > 0.05). We found out a non-significant difference in the lariowing rate between the experimental and control group of sows after the second and other inseminations (58.27% vers. 51.89: chi(2) = 1.91; P > 0.05). The number of liveborn piglets per litter after the first insemination at the comparable parity of the experimental and control group of sows (1.80 +/- 2.41 vers. 4.75 +/- 2.39 litters, t = 0.768, P > 0.05) achieved higher values after all experimental groups of boars than is the average value in the control group of sows. The results in the group of sows with the second and other inseminations were similar. The piglet production per 100 first inseminations was higher in the experimental group of farrowed sows than in the control group (+105.8 of total and +99.2 of liveborn piglets). The situation was the same with the farrowed sows after the second and other inseminations performed by the heterospermic doses in favour of the experimental group (+94.9 of total and +90.9 of liveborn piglets). The heterospermy method used in this experiment showed a positive effect in the piglet production.
