Improving the quality of whole-plant corn silage in the top layer of a silo by using an inoculant in combination with sodium benzoate

The aim of this study was to determine the effect of a commercial bacterial inoculant in combination with sodium benzoate on aerobic spoilage of whole-plant corn silage (WPCS) in the upper layer of a bunker silo. More specifically, we compared control silage (CTR) that was treated with water alone and experimental silage (OS) that was inoculated with SiloSolve® OS (a combination of Enterococcus faecium [DSM 22502/1k20602], Lactococcus lactis [DSM 11037/1k2081], and Lactiplantibacillus plantarum [DSM 16568/1k20720]) in combination with sodium-benzoate. After harvest, 1000 kg of freshly chopped corn was divided into two equal groups (OS and CTR), followed by homogenization with a pitchfork. For each group, 12 silo-NET bags (SNBs; high density polyethylene, 27 ×120 cm, 200 µm mesh pores) were filled with approximately 5.5 kg of freshly chopped forage, and then buried at a depth of 0.30 m in different regions of a bunker silo (26 m long, 8.5 m wide, 3.5 m high) for 98, 142, or 217 days. The bunker silo was divided lengthwise into two equal parts, and a 2-m buffer zone separated the CTR group and the OS group. After application of each treatment, the SNBs were removed from the ensiled mass, weighed, and mixed thoroughly, followed by measurement of chemical, fermentative, and microbiological parameters. The OS group had a decreased loss of dry matter (5.3 ± 4.72 vs. 12.5 ± 4.72 g/kg DM, P < 0.05), greater aerobic stability (302.0 ± 64.5 vs. 225.7 ± 64.5 h, P < 0.05), a lower count of yeasts (2.33 ± 0.84 vs. 3.74 ± 0.84 log10[CFU/g], P < 0.05), and a lower count of molds (2.24 ± 0.50 vs. 3.12 ± 0.50 log10[CFU/g], P < 0.05). During the feed-out phase, the temperature of the core and top layer of the bunker and the amount of WPCS waste were determined for the two groups. The temperature was consistently lower in the OS group, and the total amount of waste (2.01 % of total WPCS) was 43 % lower in the OS group. We conclude that treatment of the top layer of WPCS in a bunker silo with a commercial inoculant and sodium benzoate can decrease spoilage and increase the economic value of silage.