1. Animal Nutrition Group, Wageningen University, Wageningen 6708 WD, the Netherlands
2. Centre for Nutrition Modelling, Department of Animal and Poultry Science, University of Guelph, Guelph, ON N1G 2W1, Canada
3. Wageningen UR Livestock Research, Wageningen University Research Centre, Lelystad 8200 AB, the Netherlands
4. Department of Animal Science, University of California, Davis 95616
5. Animal Sciences, Colorado State University, Fort Collins 80523