Saavedraa, Maria José, Department of Veterinary Sciences, School of Agriculture and Veterinary Science, University of Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal saavedra@utad.pt Centre for the Research and Technology for Agro-Environment and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal, Brasil