1. Animal Production, Agricultural Research Council, Irene Campus, P/Bag X2, Irene 0062, South Africa
2. Centre for Sustainable Agriculture and Rural Development, University of the Free State, Bloemfontein 9300, South Africa
3. Unit of Animal Production, Pasture, and Forage in Arid and Subtropical Areas, Canary Islands Institute for Agricultural Research (ICIA), 38200 La Laguna, Spain
4. Department of Animal Sciences, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
5. Department of Agriculture Western Cape, Outeniqua Research Farm, George 6530, South Africa