1. Department of Veterinary Population Medicine, University of Minnesota, Minneapolis, Minnesota.
2. Departments of Food Science and Nutrition, University of Minnesota, Minneapolis, Minnesota.
3. Department of Environmental Health Sciences, University of Minnesota, Minneapolis, Minnesota.
4. Population Medicine Center, Michigan State University, East Lansing, Michigan.
5. Department of Dairy Science, University of Wisconsin, Madison, Wisconsin.
6. Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York.