Re‐ensiling and inoculant application with Lactobacillus plantarum and Propionibacterium acidipropionici on sorghum silages

Abstract

Re-ensiling of previously ensiled forage has been a common practice in Brazil, and the use of inoculants may provide a means of reducing dry-matter (DM) loss. This study aimed to determine the effect of reensiling and the use of microbial inoculants on the quality of sorghum silage. Treatments were presence/ absence of an inoculant (Lactobacillus plantarum and Propionibacterium acidipropionici) in the silage, and the re-ensiling, or not, of the material after 24 h of exposure to air, and these were tested in a factorial 2 9 2 design. Losses due to gas, effluent and total DM were assessed, as were the fermentation characteristics, chemical composition, aerobic stability, and aerobic counts of microorganisms. Effluent loss was higher in re-ensiled silage, and these silages had lower lactic acid content and higher levels of acetic and propionic acids. The in vitro DM digestibility was lower in the reensiled sorghum silages. The re-ensiled silage had higher aerobic stability. The inoculant only increased the acetic acid content of the silage. The re-ensiling of sorghum silage increased effluent loss by 71Á2%, and reduced DM digestibility by 5Á35%. The use of inoculant did not influence the quality of sorghum silage.

Quality of re-ensiled sorghum silages after prolonged periods of environmental exposure

“…The remaining silage will be available to feed cattle after the silo is opened; therefore, strategies to increase DM recovery are crucial to reduce production costs and avoid silage deficit. The DM recovered in this trial was of 90.3%, higher than that reported by Michel et al (2016) of 83% for sorghum silages re-ensiled after 24 h of air exposure. According to the results, fermentation occurs even in the material that has already fermented during the first ensilage.…”

“…Silage compaction can remove water from plant cells, resulting in effluent production, as observed in this experiment. Michel et al (2016) also observed an effluent production of 4% of the OM, after reensiling of untreated sorghum. It is important to highlight that the DM losses found here were significant during re-ensiling, and they should be considered in such conservation process, even when silage is exposed rapidly to air before re-ensiling (e.g., zero time).…”

“…However, all ensiling precautions should continue during reensiling to minimize DM losses. Michel et al (2016) observed DM losses of 13% in form of gas after re-ensiling without bacterial inoculant, indicating that DM loss can occur and may be associated to the initial condition of each silage and exposure to air. Effluent losses represent the amount of highly digestible soluble components leached, which, in turn, reduces silage quality.…”

“…This suggests that re-ensiling should be performed within this time to avoid DM and silage quality losses. However, studies on the quality of re-ensiled silages in Brazil, Israel, and the United States have shown no changes in their chemical composition after an environmental exposure of 48 h for corn, wheat (Chen & Weinberg, 2014), and whole-crop sorghum (Michel et al, 2016).…”

Nutritive value of sugarcane silages with different bacterial additives and fermentation periods

“…This may have been due to the low pH of silages (Table 1), as P. acidipropionici bacteria are intolerant to acidic conditions (at a value close to or below 4). Therefore, a silage pH below 4.2 may have inhibited bacterial growth and propionic acid production (Michel et al, 2017). Siqueira et al (2011) evaluated fresh sugarcane silage (without burning) and burned with calcium oxide (CaO) and / or L. buchneri, and observed an NDF content of 75.9 % for sugarcane silage with added L. buchneri at 60 days of fermentation, which was higher than the content of the material before ensiling.…”