1 Department of Large Animal Clinical Sciences, Michigan State University College of Veterinary Medicine, 736 Wilson Road, East Lansing, MI 48824, USA. Electronic address: vcook@cvm.msu.edu.
2 Department of Clinical Sciences, College of Veterinary Medicine and Biological Sciences, Colorado State University, 300 West Drake Road, Fort Collins, CO 80523-1678, USA. Electronic address: dhassel@colostate.edu.