Woodpulp Fines or Corn Silage as Roughages in Complete Rations or a Pelleted Complete Ration for Young Dairy Replacements 18 through 36 Weeks of Age

Twenty-eight Holstein calves were fed one of three experimental diets from 18 through 36 wk: 1) 50% woodpulp fines, 25% corn silage, and 25% concentrate; 2) 75% corn silage and 25% concentrate; and 3) a commercially available, pelleted, total calf ration. The first two rations were equivalent in roughage, vitamin, and mineral content, and all three rations were equivalent in crude protein. Average daily gain (kg), dry matter intake (% of body weight), and feed/gain for calves fed the three rations were .92, 2.42. 6.28; 1.10, 2.29, 4.07; and 1.12, 3.16, 6.73. Glucose (mg/100 ml), urea nitrogen (mg/100 ml), and B-hydroxybutyrate (mg/100 ml) in plasma from calves at 23 wk were 72.0, 5.2, .7; 72.5, 5.1, 1.9; and 82.4, 12.3, .8. The amount of butyrate (% of total), acetate/propionate, and pH of the rumen fluid from calves at 23 wk were 6.31, 2.79, 6.99; 11.74, 2.76, 7.05; and 9.89, 2.04, 6.73. Papillae length (cm) and density/cm2 ofa the rumen tissue from male calves by biopsy were: 1.83, 48.5; 2.12, 67.1; and 2.12, 27.6. Corn silage and woodpulp fines or corn silage alone can be fed to dairy calves in complete rations with satisfactory results from 18 to 36 wk of age. Additional experimentation is required to optimize quantities and proportions of these roughages in complete rations for young heifers.