1. Scott-Ritchey Research Center, 1265 HC Morgan Drive, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
2. Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
3. Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States