1. Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames 50011
2. Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011
3. Brown Loam Branch Experiment Station, Mississippi Agricultural Forestry and Experiment Station, Mississippi State University, Raymond 39154
4. Tri-County Steer Carcass Futurity Cooperative, Lewis, IA 51544
5. Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, Columbus 43210
6. Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506