Effect of a dual-purpose inoculant on the quality and nutrient losses from corn silage produced in farm-scale silos

Abstract

This project aimed to determine effects of applying an inoculant containing homofermentative and heterofermentative bacteria on the fermentation, nutritive value, aerobic stability, and nutrient losses from corn silage produced in farm-scale silos. Corn forage was harvested at 34% dry matter (DM) and treated without (control) or with 5×105 cfu/g of Lactobacillus buchneri and Pediococcus pentosaceus. The inoculant was sprayed on alternate 8-row-wide swaths of forage, and the untreated and inoculated forages were alternately packed into 3.6-m-wide bag silos. Forty-five tonnes of corn forage were packed into each of 4 replicate bags per treatment and ensiled for 166 d. Silage removed from the bags (500kg/d) was separated into good and spoiled (visibly moldy or darker) silage portions, and weighed for 35 d. Weekly composites were analyzed for chemical composition, aerobic stability, and fungal counts. Aerobic stability was measured using data loggers that recorded sample and ambient temperature every 30min for 7 d. Inoculation did not affect the chemical composition of the spoiled or good silage but decreased the quantity (5.7 vs. 12.9kg/d) and percentage (3.4 vs. 7.8) of spoiled silage in the bags by over 50%. Losses of crude protein (0.28 vs. 0.92kg/d), gross energy (6.0×104 vs. 1.8×105kJ/d), and neutral detergent fiber (1.34 vs. 4.12kg/d) in spoiled silage were less in inoculated versus control silages. Inoculated silages had lower pH (3.91 vs. 3.99), lactate concentration (7.63 vs. 7.86%), lactate:acetate ratio (1.58 vs. 2.53%), and a greater acetate (5.11 vs. 3.56%) concentration than the control silage. Inoculated silages tended to have fewer yeasts (2.59 vs. 4.62 log cfu/g) than control silages, but aerobic stability was not different across treatments (14.7 vs. 9.5h). Applying the inoculant made the fermentation more heterolactic, inhibited the growth of yeasts, and substantially reduced the amount of spoilage and the associated energy and nutrient losses. © 2012 American Dairy Science Association.