The proportion of the diet to which fibrolytic enzymes are added affects nutrient digestion by lactating dairy cows.

摘要: Eight lactating Holstein cows, four with ruminal cannulas, were used in a duplicated 4 x Latin square design to investigate fibrolytic enzyme product characterized by xylanase and cellulase activities (Promote N.E.T. Agribrands International, St. Louis, MO). The diet consisted of concentrate containing rolled barley supplement, silage alfalfa haylage (55% 45% DM basis, forage ratio) differed application: 1) control, 2) applied (45% TMR), 3) supplement (4% 4) premix (0.2% TMR). All diets that supplemented the delivered about 1.0 grams per cow day. Digestibility OM, NDF ADF total tract was increased comparison control when enzymes added entire concentrate. Enzyme treatments smaller portion showed only numerical increases digestibility over control. However, there an increase microbial N synthesis for cows fed premix. effects supplementation on milk production composition not statistically significant, but receiving had numerically higher FCM compared cows. These results indicate organic matter fiber. proportion which is must be maximized ensure beneficial response.