Nutritive value of elephantgrass and Mombaçagrass under irrigation influence and sequential grazing day
2010
Enilson Geraldo Ribeiro | Carlos Augusto de Alencar Fontes | Maria Lúcia Pereira Lima | Carlos Eugênio Martins | Antônio Carlos Cóser | Emanoel Elzo Leal de Barros
The research aimed to evaluate the influence of irrigation and sequential grazing day on chemical composition and “in vitro” digestibility of Napiergrass and Mombaça-guinea grass. The irrigation supplied the previous ten-year mean daily evapotranpiration (ET0). It was adopted the rotational grazing, with grazing period of four days, resting period of 32 days and variable stocking, with grazing pressure of four kg of leaf dry matter per 100 kg live weight. The samples were collected during eight sequential days, corresponding to the four days of occupation of two plots, using four esophagus fistulated steers. During dry season, it was not observed irrigation influence on dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin content, and on “in vitro” digestibility of extrusated DM (IVDMD) for the two grass species, but it was observed higher organic matter (OM) content in extrusa from irrigated forages. During season, forages did not differ regarding to OM, CP, ADF and lignin contents. However, Napier grass showed higher NDF content and IVDMD. During rainy season, irrigation had no influence on chemical composition or IVDMD and Napier grass showed lower contents of NDF, ADF and lignin than Mombaça grass and similar contents of DM, OM and CP and IVDMD. Regression analysis revealed linear decrease in the content of DM, CP and “in vitro” digestibility of extrusa DM (IVDMD) as the occupation period of the plot advanced, which corresponded to 4.0% a day in protein content and to 2.0% a day in IVDMD. By the other hand, the contents of NDF, ADF and lignin increased by 2.0; 4.0 and 7.0 % each grazing day, respectively.
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