Perfil de fermentação e perdas na ensilagem de diferentes frações da parte aérea de quatro variedades de mandioca

Abstract

The objective of this work was to determine fermentative profile of silage of four cassava varieties. In the study of pH, ammonia nitrogen, organic acid, dry matter (DM) recovery index and silage densities, it was used a 4 × 3 factorial arrangement, with four repetitions, four cassava varieties (Amarelinha, Olho Roxo, Periquita and Sabará) and three aerial part fractions (entire plant, surpluses of the planting and superior third). In the study of dry matter loss by gases and effluents, it was used a 4 × 3 × 7 factorial arrangement, with four replicates, composed of four cassava varieties, three aerial section fractions and seven silo opening dates (1, 3, 5, 7, 14, 28 and 56 days after ensilage). Ensilage was done in laboratory silos made of PVC pipes. The obtained data were submitted to analysis of variance and for average comparison effect, the test of Scott-Knott was performed at the 5% level of significance. There was no significant difference among pH values, organic acid and silage densities of the different varieties but pH, ammonia nitrogen and silage densities of aerial section fractions differed among varieties. Ammonia nitrogen of silages also differed among varieties. Although fresh forage had presented dry matter values lower than 30%, values of pH were satisfactory. Silages of superior-third fractions and plant remains present great fermentative quality. Silages of this study present low dry matter loss. © 2011 Sociedade Brasileira de Zootecnia.