Effect of Propionic Acid Producing Bacteria on Corn Silage Fermentation1

Abstract The effects of applying two levels of a silage additive containing Propionibacterium acidipropionici on cornsilage fermentation and aerobic stability were examined. Whole plant corn silage was ensiled for 0, 30, 60, 90, and 180 d in triplicate silo bags containing no additive; low inocula( P . acidipropionici at 1.0 × 10 4  cfu/g fresh forage); or high inocula ( P . acidipropioniciat 1.0 × 10 6  cfu/g fresh forage). After each fermentation period, silage was removed and analyzed for DM, pH, water-soluble carbohydrates, acetic, propionic, and lactic acids, total N, and ammonia N. Aerobic stability of silage was recorded upon opening silage bags at 90 and 180 d. The pH of corn silage at 0 and 30 d was lowest for high inocula treated silage. No differences were noted forwater soluble carbohydrates, acetic, propionic, or lactic acids. Ammonia N, as a percentage of total N and as a percentage of DM, was not affected by treatment except at 90 d, when high inocula treated silage was lower in ammonia N. Following 24 h of silage exposure to air, silage from all treatments were approximately 5°C greater than ambient temperature. Yeast and mold counts increased for all treatments but were not different. These data suggest that an application of P . acidipropionicito corn silage did not appreciably improve silage fermentation or aerobic stability.