1. AgResearch Ltd., Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand
2. Department of Pathobiology, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
3. AgResearch Ltd., Lincoln Research Centre, Private Bag 4749, Christchurch, New Zealand