Qualidade fermentativa e cinética de fermentação ruminal de silagem de cana-de-açúcar com aditivos

Abstract

The objective of this study was to evaluate the fermentation quality and fermentation kinetics using the in vitro semiautomatic technique of gas production by rumen microorganisms of sugar cane silages with additives. The experiment was carried out at the Department of Agricultural Sciences UNIMONTES, Campus Janaúba-MG. It was used a completely randomized design with a factorial 2 x 5, being two varieties of sugar cane (RB 86 7515 and IAC 86 2480) and five additives (urea, NaOH, CaO, corn and L. buchneri) with three replications and one treatment without additive for each variety, with the opening of the silos at 60 days after ensiling. Data were subjected to analysis of variance and treatment means (silages with additives) were compared by Scott-Knott test, varieties means by the "F" test and the control ( silage without additive) in relation to the other treatments were compared by Dunnett test, at 5% level of probability. The additives NaOH and CaO reduced the losses of gas and effluent of sugar cane silages. The IAC 86 2480 variety showed the best recovery rate of dry matter. The additives NaOH and L. buchneri reduced water activity in IAC 86 2480. Corn and L. buchneri provided lower pH values. The addition of urea significantly elevated values of ammonia nitrogen. The silages with NaOH and CaO showed high levels of lactic acid and low ethanol contents. The levels of acetic acid in percentage of dry matter were high. However, the propionic and butyric acids are within the ideal range for the fermentation process. The highest gas volume of non fiber fraction was in IAC 86 2480, with the additive NaOH. However, in the fiber fraction there was difference only between varieties with the additive urea, and the IAC 86 2480 had the highest volume. The IAC 86 2480 variety in general had the lowest times of colonization. The best results for the parameters of rumen degradability were in silages with NaOH.