1 Cattleflow Consulting and Elanco Animal Health, 2404 Walnut Grove Road, Christiana, TN 37037, USA. Electronic address: rfalkner@bellsouth.net.
2 University of Nebraska-Lincoln, School of Veterinary Medicine and Biomedical Sciences, PO Box 156, Harvard, NE 68944, USA. Electronic address: dgrotelueschen@unl.edu.
3 Livestock Veterinary Service, P.O. Box 353, 917 South Aurora Street, Eldon, MO 65026, USA. Electronic address: john@livestockvetservice.com.