1. Department of Large Animal Medicine, University of Georgia, Athens, Georgia, USA
2. Hagyard Equine Medical Institute, Lexington, Kentucky, USA
3. Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, Kentucky, USA
4. Rood and Riddle Equine Hospital, Lexington, Kentucky, USA
5. Department of Large Animal Clinical Sciences, Texas A&M University, College Station, Texas, USA