Tagasaste (Chamaecy tisusproliferus varpalmensis) feeding value and dairy sheep performance in a poor Sardinian soil

摘要

Tagasaste (Chamaecytisus proliferus Link var. Palmensis (Christ.) G. Kunkel) is a drought resistant perennial leguminous shrub well adapted to the Mediterranean environment and is utilised as a forage species in rainfed grazing systems. Eighteen randomly sampled plants of Tagasaste were studied in a 6,718 m2 experimental area with 4,464 plant ha~(-1) on poor soils in the southern Sardinia (Italy). Shrub biomass' production and plant structure were assessed monthly in winter and spring 2012. In this period, 30 mature Sarda dairy ewes were allowed to graze the area, when feeding value, secondary compounds content, biomass selected by ewes, milk production and quality were measured. In early winter, biomass was 1.4 DM ha~(-1). The growing period peaked in March when a branch increment of 41% in length and of 25% in weight was detected. In January, on average, 53% of branches' weight consisted of leaves. Nutritional value decreased during the season and twigs crude protein ranged between 238 g kg~(-1) (January) and 164 gkg~(-1) (June). A low content of formononetin and genistein were detected. In both grazing periods, sheep milk production showed an increasing trend. Tagasaste was highlighted as a potentially interesting complementary feed resource in Mediterranean dairy sheep systems, in particular, in drought marginal area and soils with severe limitations.