Evaluation of top and bottom leaf and stem fractions from tiller of three forages grasses: 1. In vitro disappearance and chemical composition

[摘要] - The degree of a simple linear correlation among the in vitro dry matter disappearance (IVDMD) and chemical composition of the leaf blades and sheath, and stems, sampled from the top and bottom tillers of dwarf elefantgrass (Pennisetum purpureum, Schumach cv. Mott, setariagrass (Setaria anceps, Stapf ex Massey cv. Kazungula) and jaraguagrass (Hyparrhenia rufa, Nees Stapf), was evaluated. A gradient pattern was observed for IVDMD, crude protein (CP) and cell wall (NDF) along the tiller profiles and difference among the tiller fractions. The leaves inserted on the top of tiller showed higher CP content and digestibility, despite of the higher NDF content than those leaves inserted on the bottom level of the tiller. The leaf blades showed a relative high IVDMD, CP and NDF than leaf sheath. No correlation was observed among the chemical components and IVDMD of the top leaf blades of the tiller. Only the lignin content showed a significant correlation (r = -0.53) with the IVDMD, when the top and bottom leaf blades were grouped. The neutral detergent fiber, acid detergent fiber, crude protein and lignin showed correlation with the IVDMD of bottom leaf blades, leaf sheath and stem.

[学科分类] 兽医学

[关键词] chemical composition;linear correlation;in vitro disappearance;Hyparrhenia rufa;Pennisetum purpureum;Setaria anceps     IntroduçãoA estimativa do valor nutritivo das forrageiras é de grande importância prática;seja para permitir adequado balanceamento de dietas à base de volumosos ou para fornecer subsídios para melhorar o valor nutritivo de forrageiras;por meio de seleção genética;técnicas de manejo mais adequadas ou;ainda;do tratamento de resíduos forrageiros