1. Texas A&M AgriLife Research, 7887 U.S. Hwy 87 N, San Angelo 76901
2. Texas A&M AgriLife Research, 1229 N. U.S. Hwy 281, Stephenville 76401
3. Department of Animal and Range Sciences, Montana State University, Bozeman 59717
4. Animal and Range Sciences Department, New Mexico State University, Box 30003, Las Cruces 88003