1. Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences , 756 51 Uppsala , Sweden
2. Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences , 750 07 Uppsala , Sweden
3. The Roslin Institute, University of Edinburgh , Edinburgh EH25 9RG , UK
4. Departamento de Mineralogía Y Petrologia, Universidad de Granada , 18002 Granada , Spain
5. Department of Medical Sciences, Uppsala University, Akademiska sjukhuset , 751 85 Uppsala , Sweden