1. Texas A&M AgriLife Research, Texas A&M University System, Overton, TX, USA;
2. Texas A&M AgriLife Research and Department of Animal Science, Texas A&M University, College Station, TX, USA;
3. USDA-ARS Livestock Issues Research Unit, Lubbock, TX, USA;
4. Mississippi Agricultural and Forestry Experiment Station, Mississippi State University, Raymond, MS, USA