Effects of inoculants containing propionic acid bacteria on fermentation and aerobic stability of corn silage

The effects of microbial inoculants containing propionic acid bacteria on fermentation and aerobic stability of corn silage were examined. Whole-plant corn was ensiled for 3, 21, and 90 d in 5- to 7-kg capacity polyethylene bags, and six treatments were compared: no additive, Pediococcus cerevisiae at 3 x 10(5) cfu/g of fresh forage plus Lactobacillus plantarum at 1.5 x 10(4) cfu/g of fresh forage, Propionibacterium acidipropionici at 1 x 10(5) cfu/g of fresh forage, Pd. cereuisiae at 1 x 10(5) cfu/g of fresh forage plus Prop. acidipropionici at 1 x 10(5) cfu/g of fresh forage, Pd. cerevisiae at 1 x 10(5) cfu/g of fresh forage plus Prop. acidipropionici at 3 x 10(5) cfu/g of fresh forage, and Prop. acidipropionici at 1 x 10(6) cfu/g of fresh forage. After each fermentation and storage period, silage was removed from each silo bag and analyzed for dry matter content, pH, water-soluble carbohydrates, lactic acid, volatile fatty acids, ethanol, total N, and ammonia N. The addition of propionibacteria either alone or with Pd. cereuisiae had little effect on pH or concentrations of water-soluble carbohydrates, lactic acid, and volatile fatty acids of the silages. Ethanol was not affected by treatment except at 90 d postfilling, when silage from forage treated with Pd. cerevisiae plus L. plantarum at the time of ensiling had the highest concentration of ethanol. Aerobic stability of the silages was recorded upon opening the silo bags at 21 and 90 d postfilling. A 2 degrees C increase in temperature generally required a longer time (about 2 h) for the silage from forage treated with Prop. acidipropionici at 1 x 10(5) cfu/g of fresh forage and in silage from forage treated with Pd. cerevisiae at 1 x 10(5) cfu/g of fresh forage plus Prop. acidipropionici at 3 x 10(5) cfu/g of fresh forage.