1. Center for Outcomes Research and Epidemiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
2. Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
3. Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
4. Midwest Veterinary Services, Inc., Oakland, Nebraska, USA.