1. Department of Veterinary Medicine, National Taiwan University, 142 Chou‐San Road, Taipei 106, Taiwan
2. Department of Clinical Veterinary Science, University of Bristol, Langford House, Langford BS40 5DU
3. Department of Small Animal Clinical Sciences, Michigan State University, D208 Veterinary Medical Center, East Lansing, MI 48824‐1314, USA
4. Centre for Veterinary Science, Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES