Valor nutricional da Brachiaria brizantha cv. marandu, sobre patejo durante a época das águas por diferentes métodos de amostragem

Abstract

The objective of this work was to evaluate the quality of B.brizantha cv Marandu forage under grazing through three sampling methods: total availability, simulated grazing and extruded grazing. Simulated grazing was manually collected by a single sampler. Total pasture availability was obtained by clearing the ground from an area enclosed by a metal frame (0.25 m2), randomly thrown into the paddocks. The extrusion was collected by ruminal emptying of four castrated steers, with an average weight of 400 kg and provided with ruminal cannula. Dry matter, crude protein and ether extract, neutral detergent fiber and acid, hemicellulose, cellulose, lignin and ash, total carbohydrates and non-fibrous carbohydrates were used. The experiment lasted 72 days, with 6 periods of 12 days, being collected on the first day of each period the samples of simulated grazing, close to the ground and ruminal extrusion. During the experimental period, the total availability of dry matter and green dry matter was 5.46 tons / ha and 3.62 tons / ha respectively. Marandu grass presented the following botanical proportion: leaf 27.31%, culm 29 , 93% and senescent material 42.77%. The values of CNF and NDF, (5.25 and 80.47) were higher for close-to-ground cutting compared to the other systems, simulated and extruded grazing, this was due to the lower ground-carbohydrate content, since At the base the material is always more fibrous and with regrowth beginning it is possible to have tiller, in this context, starting the deposition carbohydrate and already lignified, on account of the base. Aiming to reconcile yield and chemical composition of Marandu grass forage in different sampling methods. Close to Ground Cut, Simulated Grazing and Extruded. According to the results, the Extrusa sampling method was that obtained higher, crude protein and ash contents, and lower fiber and neutral detergent and acid detergent fiber contents.