EFFECTS OF AN ENZYME MIXTURE, AN INOCULANT, AND THEIR INTERACTION ON SILAGE FERMENTATION AND DAIRY PRODUCTION

Second-crop, mixed grass-legume forage was ensiled in four bunker silos either untreated or after application at the forage harvester of an enzyme mixture containing cellulase, xylanase, cellobiase, and glucose oxidase, a commercial inoculant, or both additives combined. Sixteen multiparous midlactation Holstein cows in a 4 x 4 Latin square design received each silage in a 50:50 forage: concentrate diet to determine effects of silage additives on milk production and composition. Enzyme treatment reduced silage pH, concentrations of xylose and total sugars, and concentration and proportion of cell-wall arabinose. Titratable acidity, buffering capacity, concentration of residual water-soluble carbohydrate, and digestibility of DM in vitro were increased, and levels of silage structural carbohydrates were reduced. Inoculation, both alone and in the combined treatment, reduced silage pH compared with control, but inoculation alone was more effective than the combination. Enzyme treatment increased DMI and production of milk, FCM, SCM, milk protein, and milk SNF. The two silage additives were antagonistic when combined and did not improve silage fermentation, nutritional value, or animal performance, and enzyme degradation of forage structural carbohydrates was reduced. Inoculation also reduced silage aerobic stability. Combination of enzyme systems with inoculants requires careful evaluation to avoid antagonistic interactions.