1. TOPIGS Research Center IPG, P.O. Box 43, 6640 AA Beuningen, The Netherlands
2. Animal Breeding and Genomics Centre, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands
3. Animal Nutrition Group, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands