Department of Genetics and Biometry, Research Institute for Biology of Farm Animals, Wilhelm-Stahl Allee 2, D 18196 Dummerstorf, Germany. repsilber@fbn-dummerstorf.de|Department of Genetics and Biometry, Research Institute for Biology of Farm Animals, Wilhelm-Stahl Allee 2, D 18196 Dummerstorf, Germany. repsilber@fbn-dummerstorf.de|Department of Genetics and Biometry, Research Institute for Biology of Farm Animals, Wilhelm-Stahl Allee 2, D 18196 Dummerstorf, Germany. repsilber@fbn-dummerstorf.de|Department of Genetics and Biometry, Research Institute for Biology of Farm Animals, Wilhelm-Stahl Allee 2, D 18196 Dummerstorf, Germany. repsilber@fbn-dummerstorf.de|Department of Genetics and Biometry, Research Institute for Biology of Farm Animals, Wilhelm-Stahl Allee 2, D 18196 Dummerstorf, Germany. repsilber@fbn-dummerstorf.de|Department of Genetics and Biometry, Research Institute for Biology of Farm Animals, Wilhelm-Stahl Allee 2, D 18196 Dummerstorf, Germany. repsilber@fbn-dummerstorf.de|Department of Genetics and Biometry, Research Institute for Biology of Farm Animals, Wilhelm-Stahl Allee 2, D 18196 Dummerstorf, Germany. repsilber@fbn-dummerstorf.de|Department of Genetics and Biometry, Research Institute for Biology of Farm Animals, Wilhelm-Stahl Allee 2, D 18196 Dummerstorf, Germany. repsilber@fbn-dummerstorf.de|Department of Genetics and Biometry, Research Institute for Biology of Farm Animals, Wilhelm-Stahl Allee 2, D 18196 Dummerstorf, Germany. repsilber@fbn-dummerstorf.de