1. INRA, UMR1348 PEGASE, Agrocampus Ouest, UMR1348 PEGASE, 35590 Saint-Gilles, France, 35000 Rennes, France
2. Agriculture and Agri-Food Canada, Dairy and Swine R & D Centre, Sherbrooke, QC, J1M 0C8, Canada
3. Department of Animal Science, Aarhus University, Research Centre Foulum, Blichers Álle 20, Post box 50, 8830 Tjele, Denmark