Milk yield and composition of Holstein dairy cows fed different forage to concentrate ratio as well as different lipid contents in the diets were studied. Eight cows with 58±9 days in milk and average production of 28±4 kg/day were assigned in a double Latin square design 4 x 4, in a 2 x 2 factorial arrangement. Treatments were diets with high forage and low lipid levels, high forage and high lipid levels, low forage and low lipid levels and low forage and high lipid levels. Milk yield and fat corrected milk yield (3.5%) were not affected by treatments (P>0.05). The reduction on forage ratio in the diet decreased milk fat percentage and production (P<0.05). The increase in lipid levels in the diets reduced total milk solids as well as milk urea nitrogen concentrations (P<0.05).
dairy cow; concentrate; forage; milk fat; soybean extruded
