1. Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY 40546, USA
2. College of Veterinary Medicine, Lincoln Memorial University, Harrogate, TN 37752, USA
3. McGee Medical Center, Hagyard Equine Medical Institute, 4250 Iron Works Pike, Lexington, KY 40511, USA