1. Scott-Ritchey Research Center; College of Veterinary Medicine; Auburn University; Auburn; AL; USA
2. Department of Anatomy, Physiology, and Pharmacology; College of Veterinary Medicine; Auburn University; Auburn; AL; USA
3. Department of Animal and Rangeland Sciences; Oregon State University; Corvallis; OR; USA
4. Department of Pathobiology; College of Veterinary Medicine; Auburn University; Auburn; AL; USA