1. Agriculture and Agri-Food Canada, Dairy and Swine R & D Centre, 2000 College St., Sherbrooke, QC, J1M 0C8, Canada
2. Michigan State University, Department of Animal Science, 2209 Anthony Hall, East Lansing, MI 48824, USA
3. INRA-Agrocampus Ouest, UMR1348 PEGASE, 35590 Saint-Gilles, France