Qualidade da silagem do capim Marandu manejado sob diferentes alturas de dossel

Abstract

It was aimed to evaluate the quality of Urochloa brizantha (former Hochst. Rich) Stapf cv. Marandu silages managed under different sward heights. The experiment was carried out in the Experimental Farm of UNIMONTES, located in Janaúba/MG district. A design was used in blocks at random, with 4 sward heights (30, 45, 60 and 75 cm) in 5 blocks, totaling 20 experimental units. The grassy was stored in experimental silos of PVC, with known weight. The silos’ opening was accomplished to 56 days after storage. Before the opening, to 56 days of storage, the silos were weight to evaluate the losses for gases and soon afterwards, open for the silage retreat and weighting of the sand of the silo’s bottom to quantify the losses for effluents. Were determined the pH values, NNH3, organic acids content (lactic, acetic and butyric), silages Wa, and still MS, ashes, PB, FDN, FDA, lignin, NIDN, NIDA, EE, CT, CNF, CF and NDT contents, in the forage in natura and in the silage. The collected data were submitted to the variance analysis, and when significant the averages of treatments were submitted to regression study (p<0,05), using SISVAR program (FERREIRA, 2000). The grassy handled to 30 cm resulted in silages with better fermentative characteristic, presenting larger acid lactic content, smaller losses during the fermentation and larger conservation of the crude protein. The increase in the sward height determined increments in the fiber contents and unavailable nutrients. It was concluded that the sward height of 30 and 45 cm of Marandu grass resulted in a silage of better nutritional value when compared the other appraised heights.