Optimierung der zuchtung innerhalb einer geschlossenen zuchtlinie mit schwacher inzuchtrate

Abstract The design of a selection programme within a closed line of pigs should take account of genetic progress, development of inbreeding and economic management. From a simulation study of a closed herd situation where all male and female offspring were performance tested, it was concluded that: • - Selection via sows gives maximum genetic progress when the sows produce between 2 and 3 litters. • - The best compromise between the annual increase in degree of inbreeding and genetic progress is obtained by selecting 15–20 boars each year, i.e. 1 boar every 3 weeks, and eliminating the oldest boar at the same time. Finally, the genetic and economic analysis has shown that it is not very realistic to design a selection programme in a closed line when the herd size is below 100 sows.