Value of endemic legumes for livestock production on Caatinga rangelands

Abstract

Rangelands and other native pastures occupy a large area of the planet, with greater temporal and spatial botanical composition and productivity variability. Despite the continuous and historical use of these areas, including overgrazing and fire exclusion, endemic legume species persist in some semiarid rangelands. The objective this work was to review current knowledge of legume use, especially those of the Brazilian Caatinga rangeland. Studies that measure the qualitative and quantitative variations of native legumes are essential for ruminant feed supplementation, to the sustainability of animal production, as well as for economic and environmental improvements in rangelands. Caatinga vegetation of northeastern Brazil consists of deciduous shrubs and small trees which mostly lose their leaves at the beginning of the dry season. The legume family contributes to the greatest number of endemic species but little is known about their productivity or nutritive values. Livestock select Orelha de onça [Macroptilium martii (Benth.) Marechal & Baudet] and Mororó (Bauhinia cheilantha (Bong.) Steud.) and these should, during rangeland clearing, be preserved. In addition, although Caatinga legumes have great crude protein content, their biological fixation of atmospheric N has yet to be thoroughly studied. On the negative side, some native Caatinga legumes have great levels of neutral detergent fiber-bound N (NDFN) and condensed tannin. As a result, animal performance in Caatinga is often poor, notably in the dry period. Forage legumes also provide several environmental services such as N input via BNF and rehabilitation of degraded land.