1. William T. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA
2. Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA
3. K. L. Maddy Equine Analytical Pharmacology Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, CA
4. Department of Pharmacology, Toxicology Research Laboratory, College of Medicine, University of Illinois, Chicago, IL