1. From the Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL 61501 (Constable, Morin, Nelson); Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506 (St. Jean); and Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210 (Hull, Rings).