[1] Univ British Columbia, Fac Land & Food Syst, Anim Welf Program, 2357 Main Mall, Vancouver, BC V6T 1Z6, Canada
[2] Wageningen Univ & Res, Anim Prod Syst Grp, POB 338, NL-6700 AH Wageningen, Netherlands
[3] Wageningen Univ & Res, Livestock Res, POB 338, NL-6700 AH Wageningen, Netherlands
[4] Louis Bolk Inst, Kosterijland 3-5, NL-3981 AJ Bunnik, Netherlands