RESUMO
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 concentration of forage, a control diet with a low concentration of forage, and three diets in which dried brewers grains replaced a portion of the forage, 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 differences in ruminal pH or rates of passage caused by treatment were detected. Although brewers grains had slower digestion rates of neutral detergent fiber (NDF) in situ and faster passage rates than did alfalfa, brewers grains had minor effects on site of NDF digestion. Intake of dry matter was depressed by the higher NDF concentrations in diets in which brewers grains replaced concentrate, but a long-term feeding study is needed to verify this conclusion. Although brewers grains did not appear to be very effective at stimulating milk fat percentage, dry matter intake was maintained when brewers grains replaced forage, and it appears that brewers grains can successfully replace a portion of the forage NDF in the diets of lactating cows.
