1. Department of Animal Science, University of Nebraska-Lincoln , Lincoln, NE 68583 , USA
2. Department of Biological Systems Engineering, University of Nebraska-Lincoln , Lincoln, NE 68583 , USA
3. Department of Animal Sciences, University of Illinois at Urbana-Champaign , Urbana, IL 61801 , USA
4. West Central Research and Extension Center, University of Nebraska-Lincoln , North Platte, NE 69101 , USA