Efeito da reensilagem e do uso de inoculante microbiano na silagem de sorgo

Abstract

The silage process is one of the most used techniques in the world for the conservation of fodder destined to feed cattle. During the last years the commercialization of silages among the farmers has been increasing, which means that the material that was stored on anaerobic conditions, is exposed to the air to later be compact and sealed. In order to improve the fermentation process during the anaerobic phase and increase the stability of the silage upon exposure to the air, microbial additives have been used to accelerate the fermentation process and / or to produce acids which act to control the growth of undesirable microorganisms. The objective of this study was to evaluate the effect of re-ensiling and the use of microbial inoculant containing Lactobacillus plantarum and Propionobacterium acidipropionici on sorghum silage quality. The treatments consisted of conventional sorghum silage, re-ensiled sorghum silage after 12 hours of exposure to air, conventional sorghum silage inoculated with microbial additive and sorghum silage re-ensiled and inoculated with microbial additive. The re-ensiling process did not affect the chemical composition of the sorghum silages, however the use of inoculant increased the levels of NFD, NFDcp and reduced the contents of NFC and IVDMD. Regarding the fermentation parameters, re-ensiled silages had lower levels of lactic acid and higher contents of propionic acid than conventional silages. On the other hand, the use of inoculant in addition to reducing lactic acid contents and increasing propionic acid contents, increased the pH of the inoculated material. The re-ensiled materials showed higher effluent losses than conventional silages. The use of inoculant provided higher losses of effluents, gases and total dry matter than non-inoculated silages. There was no difference between the treatments during the aerobic stability test of the materials, however, inoculated silages showed higher pH at the end of the test and lower yeast growth than the non-inoculated silages. Sorghum re-ensiling after 12 hours of exposure to air did not affect sorghum silage quality. However the use of inoculant did not represent improvements in the fermentative process of the material.