EFFECTS OF REPLACING FORAGE FIBER OR NONFIBER CARBOHYDRATES WITH DRIED BREWERS GRAINS

Four primiparous Holstein cows in late lactation were used in a 4 x 5 Youden square design. Each cow was fitted with ruminal, duodenal, and ileal cannulas. Treatments were a control diet with a high concentrati on of forage, a control diet with a low concentration of forage, and t hree diets in which dried brewers grains replaced a portion of the for age, concentrate, or both. Cows were fed and milked twice daily in 14- d periods. Chromic oxide and Yb (soaked in acid) were used as markers for digesta flow and rate of passage, respectively. No significant dif ferences in ruminal pH or rates of passage caused by treatment were de tected. Although brewers grains had slower digestion rates of neutral detergent fiber (NDF) in situ and faster passage rates than did alfalf a, brewers grains had minor effects on site of NDF digestion. Intake o f dry matter was depressed by the higher NDF concentrations in diets i n which brewers grains replaced concentrate, but a long-term feeding s tudy is needed to verify this conclusion. Although brewers grains did not appear to be very effective at stimulating milk fat percentage, dr y matter intake was maintained when brewers grains replaced forage, an d it appears that brewers grains can successfully replace a portion of the forage NDF in the diets of lactating cows.