William O. Reece, DVM, PhD is University Professor Emeritus in the Department of Biomedical Sciences, College of Veterinary Medicine, at Iowa State University of Science and Technology in Ames, Iowa, USA. Eric W. Rowe, DVM, PhD, is Associate Professor in the Department of Biomedical Sciences, College of Veterinary Medicine, at Iowa State University of Science and Technology in Ames, Iowa, USA.