The role of scattered Narrow-leafed ash of lameiro systems on livestock production in Northeast Portugal

The lameiro is the silvo-pastoral system specific to the region of Trás-os-Montes Northeast Portugal, comprising a natural herbaceous formation in association with specific riparian trees. Among them, the ash (Fraxinus angustifolia, Vahl) is the most frequent. Ash occurs in the meadows as scarlet trees or as a line trees. Usually, the meadows aren’t grazed from March to June, in order to get the hay. From June to March, the meadows are directly consumed by the livestock such as cattle or sheep. As output from the system, the trees furnish firewood and timber. At the same time that they furnish shelter, they also furnish leaves, which constitute an important complement to the natural pastures in the diet of animals. In addition, trees have an important ecological effect. Animal products like meat and milk constitute another of the outputs of the system. Also, the hay is a commercial product. The density of trees ranges from about 5 ha-1 to 20 ha-1 depending on soil conditions and on the main objective of the exploitation. Traditionally, the timber is sold in special moments of financial needs. The ash trees act as a security funding for the farmers and as a complement to the needs of livestock in the scarcity periods. Traditionally, the branches are lopped and are used as fodder, in the middle summer, when the herbaceous component is dried. Occasionally the branches are dried for used as winter forage. The objective of this study is to analyse the performance of woody component of lameiro from livestock perspective, particularly to study the chemical composition and in vitro digestibility of ash tree leaves harvest at different mature stages. Also, the leaves production was assessed. The average production of ash leaves is 2.6 t ha-1year-1. The digestibility in vitro of ash leaves ranges from 74.6% (July) to 81.0% (August). The crude protein varies from 14.4% DM in early July to 11.5% DM in final September, when the signs of senescence appear. The acid detergent lignin (ADL) contents ranged from 10.6% DM in early July to 8.8 % DM in final September. The ash tree leaves can be seen as an important feed resource during the dry season for the livestock