1. School of Agriculture and Food Sciences, Animal & Wildlife Sciences Group, The University of Queensland, QLD 4343 Gatton, Australia
2. Wageningen University, Adaptation Physiology Group, P.O. Box 338, 6700 AH, Wageningen, the Netherlands
3. Wageningen University, Technical Services, P.O. Box 338, 6700 AH, Wageningen, the Netherlands