Estabilidade aeróbia de silagem de dieta total submetida a diferentes tempos de estocagem com ou sem a presença de aditivo

Abstract

Total diet silage is a technology that aims to improve the digestibility of preserved foods, optimize the use of wet co-products and serve farms that have limitations in providing total diet. However, as it is a recent practice in Brazil, studies on the quality of this conservation are still scarce. The objective of this work was to evaluate the aerobic stability of the total diet silage with or without additive and submitted to different storage times. The experimental design was completely randomized in a 2 × 4 factorial arrangement, with additive factors (with and without) and storage times (0, 15, 30 and 60 days). The additive used was buffered propionic acid at a dose of 500 ml per ton of fresh diet. For each treatment 3 bales were made, making a total of 24 silos. Data were subjected to nonparametric analysis and compared by the Kruskal-Wallis test at 5% probability using the Action 2.9 statistical software. Aerobic stability, maximum temperature, number of hours to reach maximum temperature, average temperature and the resulting accumulated temperature were evaluated as the sum of the average daily temperature difference in silages exposed to air from 0 to 5 and 0 to 10 days. There was no effect of the additive on aerobic stability. The fresh diet (time 0) lost stability after 13.8 hours of exposure. Silages stored for 15 days or more remained stable throughout the evaluation period (240 hours). The in natura diet (time 0) presented higher accumulated temperature in 5 (17.0 ºC) and 10 days (39.4 ºC) in relation to the other storage times, which were similar to each other. The average temperature decreased with increasing storage time. The maximum temperature and the time in hours to reach it also reduced with the advance of the storage period, but stabilized from 30 days of storage. The additive did not influence any of the evaluated temperature parameters. The use of buffered propionic acid was not efficient in improving the aerobic stability of total diet silage. In order to prolong aerobic stability, a minimum storage period of 15 days is required for total diet silage.