1. Dep. of Agriculture, Agribusiness and Environmental Science; Texas A&M Univ. Kingsville; Kingsville TX 78363
2. Dep. of Environmental Science and Technology; Univ. of Maryland; College Park MD 20742
3. USDA-ARS Pasture Systems and Watershed Management Research Unit; Building 3702, Curtin Rd. University Park PA 16802
4. Dep. Of Animal, Rangeland and Wildlife Sciences; Texas A&M Univ. Kingsville; Kingsville TX 78363