[1] Univ Guelph, Ctr Nutr Modelling, Dept Anim & Poultry Sci, Guelph, ON N1G 2W1, Canada
[2] Univ Leon, Dept Anim Prod, Leon 24007, Spain
[3] Univ Wageningen & Res Ctr, Anim Sci Grp, NL-8200 AD Lelystad, Netherlands
[4] Inst Food Res, Inst Grassland & Environm Res, Aberystwyth SY23 3EB, Dyfed, Wales
[5] Univ Wageningen & Res Ctr, Inst Anim Sci, Anim Nutr Grp, NL-6709 PG Wageningen, Netherlands