1. Nebraska Veterinary Diagnostic Center, School of Veterinary Medicine and Biomedical Sciences, University of Nebraska–Lincoln, Lincoln, NE 68503, USA
2. Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA
3. Department of Pathobiology and Population Medicine, Mississippi State University, Mississippi State, MS 39762, USA
4. United States Department of Agriculture (USDA), Agricultural Research Service (ARS), United States Meat Animal Research Center, Clay Center, NE 68933, USA