1. South Dakota State University, Agricultural and Biosystems Engineering, 1400 North Campus Drive, Brookings, SD 57007.
2. USDA-ARS, North Central Agricultural Research Laboratory, 2923 Medary Ave, Brookings, SD 57006.
3. Corresponding author. Phone: 605-693-3241. Fax: 605-693-5240. E-mail: krosentr@ngirl.ars.usda.gov
4. South Dakota State University, Wildlife and Fisheries Sciences, Brookings, SD 57007.