1. Animal Production Department, Centro de Investigacións Agrarias de Mabegondo, Xunta de Galicia, 15318 A Coruña, Spain
2. Independent Researcher, 27002 Lugo, Spain
3. Department of Agroforestry Engineering, Higher Polytechnic Engineering School, Campus Terra, University of Santiago de Compostela, 27002 Lugo, Spain