Abstract

LOPEZ-VIGOA, Onel et al. Evaluation of the nutritional value of forages in a silvopastoral system. Pastos y Forrajes [online]. 2019, vol.42, n.1, pp.57-67. ISSN 0864-0394.

The objective of the study was to evaluate the effect of season on the forage production and nutritional value, in an association of Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs with Leucaena leucocephala (Lam.) de Wit. The herbaceous component and tree stratum were sampled; and the availability and chemical composition in the grass, twining legume and tree were estimated. The grass availability was high in both seasons, but higher (p < 0,001) in the rainy season (RS) with regards to the dry season (DS), with values of 5 895,2 and 3 763,1 kg DM/ha/rotation, respectively. The availability of L. leucocephala foliage was similar for both seasons (85,7 and 72,1 kg DM/ha/rotation for the RS and DS, respectively). The IVDMD96 in M. maximus was adequate (≈ 650 g/kg DM) and similar for both seasons. The ME showed higher values (p < 0,001) in the RS (7,8 vs 7,0 MJ/kg DM). The CP was higher (p = 0,004) in the DS (13,8 vs 11,4 %), while the NDF and ADF did not differ between seasons. In L. leucocephala the IVDMD96 (p = 0,003), ME (p = 0,009) and CP (p = 0,003) were higher in the DS compared with the RS (601,5 vs 545,1 g/kg DM; 7,3 vs 6,8 MJ/kg DM; 27,9 vs 24,8 %, respectively). In Neonotonia wightii (Wight & Arn.) J.A. Lackey all the indicators were similar for both seasons, with an excellent IVDMD96 (641,4-667,2 g/kg DM) and CP (18,1-20,6 %) and adequate ME (7,4-7,7 MJ/kg DM). The association of cultivated grasses with L. leucocephala, under production conditions, showed high availability of total biomass and CP per hectare; which although higher in the rainy season, showed the potential of these systems to guarantee adequate food production throughout the year.

Keywords : chemical composition; nutrient availability; Leucaena leucocephala; Megathyrsus maximus.

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