1. Soil and Crop Science Dep.Texas A&M Univ., Agricultural Research and Extension CenterOvertonTX75684
2. Agronomy Dep.Univ. of FloridaGainesvilleFL32611‐0300
3. Dep. De Zootecnia/UFRPEAv. Dom Manoel de Medeiros, S/NDois Irmaos52171‐900Recife‐PEBrazil
4. Dep. of Animal and Poultry SciencesVirginia Polytechnic and State Univ.BlacksburgVA24061‐0306
5. Dep. of Animal SciencesUniv. of Florida Range Cattle Research and Education CenterOnaFL33865