EFFECT OF ENZYME ADDITIVES ON QUALITY OF ALFALFA GRASS-SILAGE AND DAIRY-COW PERFORMANCE

First- and second-cut alfalfa/grass forage crops were wilted to approx imately 40% dry matter (DM) and ensiled untreated (control) or treated with either of two enzyme additives to determine the effects on silag e quality and animal performance of crops that contain different ratio s of legume to grass. An alfalfa enzyme mix (Alfa) contained cellulase , amylase and glucose oxidase: a grass enzyme mix (Grass) was similar but contained no amylase. Both additives contained identical inoculant s of lactobacillus. Silage was fed to mid-lactation Holstein cows at 6 0 d (second cut) and 120 d (first cut) postensiling using repeated Lat in square designs. Silage samples and animal performance data were col lected during the last 7 d of each of three 28-d feeding periods that comprised each Latin square. Colony-forming units of lactic acid bacte ria. concentrations of water-soluble carbohydrate (WSC), ammonia N, ac id-detergent fiber N and organic acids. pH, DM disappearance, and temp erature changes during ensiling were measured to assess silage quality . Six sheep were also used in a repeated Latin square design to determ ine digestibility of the second-cut silages. First-cut silage, which c ontained about 50% timothy, and 50% alfalfa was qualitatively similar across treatments except for a lower (P < 0.05) concentration of hemic ellulose in Grass-treated silage. The only effect (P < 0.05) on qualit y of second-cut silage, which contained about 80% alfalfa and 20% timo thy, was an increase in estimated DM loss in Grass-treated silage comp ared with Alfa and the control. Despite the negligible effects on sila ge quality parameters. Grass slightly depressed (P < 0.10) the yield o f fat-corrected milk in cows fed first-cut silage, and DM intake of co ws fed second-cut forage was elevated slightly (P < 0.05) and fat perc ent was depressed (P < 0.05) by Alfa relative to the control. Conseque ntly, although the change was small, enzyme treatment of forages may r epresent a means of reducing the fat percent of milk. Sheep consumed m ore (P < 0.05) second-cut silage treated with Alfa, and DM digestibili ty was higher (P = 0.09) when compared with the control. An enzyme mix ture containing amylase may be marginally more effective when forage m ixtures contain more alfalfa than timothy.