Seasonal grazing of goats and sheep on Mediterranean mountain rangelands of northeast Portugal

• Autor(a) principal: Castro, Marina
• Data de Publicação: 2016
• Outros Autores: Fernández-Núñez, Esther
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10198/12923
• topic: Diet diversity; Diet overlap; Diet selection; Small ruminants

The objective of this study was to compare the feeding strategies between sheep and goat rearing by shepherds in the Mediterranean mountain area of northeast Portugal. For this purpose, grazing itineraries, diet selection, diet overlap and the diet diversity of different flocks of sheep and goats were studied. The flocks were monitored along specific grazing circuits every three months. Grazing itineraries were recorded by means of a hand global positioning system (GPS). Diet composition was determined by direct observation method in pre-set intervals of 15 minutes during the day. For each observation point, herbaceous communities, shrubs and tree species consumed were recorded. Diet selection was estimated by Krueger’s preference index and the degree of overlap between diets was estimated using the Kulczynskis similarity index. The diet of goats had a significantly higher content of shrubs (27%) and trees species (24%) than sheep (6% and 10% respectively). Sheep diet comprised 84 % of herbaceous plants, whereas this group only represented 49 % in goat diet. Erica sp. and Rubus sp. were the shrubs with the highest preference index for goats. Both animals avoided Cytisus multiflorus in winter and spring, and Cistus ladanifer in summer. Goats showed a higher preference for Fraxinus excelsior and Quercus rotundifolia. Goat diversity of forage on offer and animal diet was significantly higher than on the sheep diet. Plant species diversity in sheep and goat diets significantly increased in autumn compared to spring. The average of diets’ overlap was higher during the winter and lower in summer. The length of grazing itineraries and diet diversity reflects the level of dependence on natural resources and consequently it´s level of extensification.