1. Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 114, 3584 CM Utrecht, The Netherlands
2. Dierenkliniek de Vijfsprong, Vijfsprongweg 28, 6733 JJ Wekerom, The Netherlands
3. Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA
4. Department of Clinical Sciences and Services, Royal Veterinary College, London AL9 7TA, UK