1. Department of Veterinary Physiology, Pharmacology and Toxicology, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803,
2. Analytical Toxicology Laboratory, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43201,
3. Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA 19348,
4. Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40506, USA