Incorporation of QTL information into routine estimation of breeding values for German Holstein

Summary: Since 1995 young bulls from German dairy population have undergone routine genotyping. These molecular markers are used both for parentage testing and for marking regions harbouring quantitative trait loci (QTL) influencing traits characterising production performance of dairy cattle. Originally, genotypes of 339 markers have been identified to screen for most likely positions of QTL with largest effects. In the following step a subset of 13 markers has been chosen for routine genotyping. The current genotyped population comprises genotypes of 5278 individuals. The national data management and analysis system developed for handling the molecular information and for genetic evaluation under the mixed inheritance model (i.e. separating polygenic and QTL components) is presented. Specifically, two main goals of this contribution are (i) to introduce statistical models used for the incorporation of QTL information into the routine estimation of breeding values and (ii) to present first estimates of QTL and polygenic variance components for the whole genotyped population of German Holsteins