Effect of aerobic exposure time and use of inoculants on chemical, fermentative, and digestibility characteristics of relocated whole-plant corn silages

ABSTRACT The current study evaluated the impact of aerobic exposure time (ET) and microbial inoculants (MI) on the fermentative and microbiological characteristics and the nutritional value of relocated whole-plant corn silage (WPCS). Treatments were arranged in a 4 × 5 factorial design: microbial inoculants (without inoculant (WI); L. plantarum (DSM3676; DSM3677) + L. buchneri (DSM13573) (LPLB); L. plantarum (MA18/5U) + P. acidipropionici (MA26/4U) (LPPA); and L. buchneri (DSM13573) (LB)) and non-relocated (NR) or relocated after 12, 24, 48, and 60 h of ET. In the NR silage, the total storage time was 120 (not exposed-ET 0 h) or 210 (NR) days. Fresh forage that included an inoculant was inoculated with 1 × 105 CFU g−1 of forage. Samples were collected after 120 days of ensiling at various exposure times, and again after an additional 90 days of fermentation. For the samples collected at the initial opening (120 days), exposure time was not included as a factor in the statistical model. After 120 d of ensiling, inoculated silage exhibited higher lactic and propionic acid and lower ethanol concentrations, lower yeast counts, and reduced dry matter losses. During exposure, yeast counts increased (P<0.01) in WI silages after ET 0 (3.50 CFU g−1) to 60 h (4.90 CFU g−1). Post-relocation, the mold counts in WI silage were greater (P<0.01) when NR (4.02 CFU g−1) and relocated at 12 h (4.1 CFU g−1) and 24 h (4.2 CFU g−1) compared with other silages. The in vitro dry matter digestibility of LB silage decreased (P<0.01) from NR (674.7 g kg−1 DM) to 60 h (592.6 g kg−1 DM). The LB silage exhibited reduced aerobic stability. L. buchneri inoculation enhances the digestibility of corn silage ensiled for 210 d, but the digestibility is reduced from 24 h of aerobic exposure.