The effect of Lactobacillus buchneri 40788 or Lactobacillus plantarum MTD-1 on the fermentation and aerobic stability of corn silages ensiled at two dry matter contents

Whole-plant corn was harvested at 33 (normal) and 41% (moderately high) dry matter (DM) and ensiled in quadruplicate 20-L laboratory silos to investigate the effects of Lactobacillus buchneri 40788 (LB) or L. plantarum MTD-1 (LP) alone, or in combination, on the fermentation and aerobic stability of the resulting silage. Aerobic stability was defined as the amount of time after exposure to air for the silage temperature to reach 2°C above ambient temperature. The chopped forage was used in a 2 x 2 x 2 factorial arrangement of treatments: normal and moderately high DM contents, LB at 0 (untreated) or 4 x 10⁵ cfu/g of fresh forage, and LP at 0 or 1 x 10⁵ cfu/g. After 240 d of ensiling, corn silage harvested at the moderately high DM had higher pH, higher concentrations of ethanol, and more yeasts compared with the silage ensiled at the normal DM content. Inoculation with LB did not affect the concentration of lactic acid in silages with a moderately high DM, but decreased the concentration of lactic acid in the silage with normal DM. Higher concentrations of acetic acid were found in the silage treated with LB compared with those not treated with this organism. Inoculation with LP increased the concentration of lactic acid only in the silage with the normal DM content. The concentration of acetic acid was lower in silage treated with LP with a moderately high DM content, but greater in the silage treated with LP with the normal DM content when compared with silages without this inoculant. Appreciable amounts of 1,2-propanediol (average 1.65%, DM basis) were found in all silages treated with LB regardless of the DM content. The addition of L. buchneri increased the concentration of NH₃-N in silages but the addition of L. plantarum decreased it. Aerobic stability was improved in all silages treated with LB, with greater aerobic stability occurring in the silage with moderately high DM compared with silage with normal DM content. Inoculation with LP had no effect on aerobic stability. There were no interactions between L. buchneri and L. plantarum for most fermentation products or aerobic stability of the silages. This study showed that inoculating whole-plant corn with L. buchneri 40788 or L. plantarum MTD-1 has different beneficial effects on the resulting silage. There appear to be no major interactions between these organisms when added together to forage. Thus, there is potential to add both organisms simultaneously to improve the fermentation and aerobic stability of corn silage.