Affiliation: | 1. Livestock Veterinary Service, 917 South Aurora/ PO Box 353, Eldon, MO 65026, USA;2. College of Veterinary Medicine, University of Minnesota, 225 Veterinary Medical Center, 1365 Gortner Avenue, St Paul, MN 55108, USA;3. University of Nebraska, School of Veterinary and Biomedical Sciences, Great Plains Veterinary Educational Center, 820 Road 313/ PO Box 148, Clay Center, NE 68933, USA |