Marandu grass silage fermentative characteristic managed under different sward heights

Abstract

The objective of this study was to evaluate the fermentation characteristics of Brachiaria brizantha Hochst ex. Rich) Stapf cv. Marandu managed under different sward heights. We used a complete randomized block delimitation layout, with four sward heights (30; 45; 60 and 75cm) in 5 blocks totaling 20 experimental units. The grass was packed and weighted in PVC silos. The silos were opened again at precisely 56 days after ensiling. Moments before opening the silos after the 56 days of storage, these silos were first weighted to measure any weight loss due to the production of gasses during fermentation, and then opened to remove the silage and to quantificate of the effluent losses. The pH, ammonia and acids levels were then measured, along with the levels of organic (lactic, acetic, butyric) and dry matter. The data collected were subjected to variance analysis and when any significant average of treatment was found, a regression study was done. The grass silage measuring up to 30 and 45 cm resulted in silages with better fermentation characteristics. It presented higher lactic acid content, lower butyric acid and ammoniacal nitrogen contents and lower losses during fermentation. The grass silage measuring up to 60 and 75cm presented a totally inadequate fermentation process for the conservation of fodder, been classified as being of poor quality. It is concluded that the Marandu grass with height of 30 and 45cm showed the best silage fermentation characteristics when compared to other evaluated heights, but did not reach a level of quality desired.