Date of this Version
Fixed genetic groups have been defined arbitrarily in linear models for sire evaluation. This simulation examined genetic groups under several selection strategies. Sires with highest estimated transmitting abilities were selected to have sons and additional female progeny. The process of evaluation and selection of sires and dams was continued for four generations. Final estimates of transmitting ability were compared to actual transmitting ability for several sire evaluation models on 300 simulated data sets. Genetic groups defined by generation increased the accuracy of estimating sire transmitting abilities over ignoring genetic groups when selected dams and sires of young bulls were mated. A joint selection model was presented which assists in interpreting results of simulation.