EFFECTS OF TREATING OAT HULLS WITH ALKALINE HYDROGEN-PEROXIDE ON INTAKE AND DIGESTION BY MIDLACTATION DAIRY-COWS

Twelve Holstein cows, averaging 110 d postpartum, were used in three replications of a 4 x 4 Latin square design to determine the effects of feeding different amounts of alkaline hydrogen peroxide-treated oat hulls on digestion and production responses. Complete mixed diets were 35% concentrate (DM basis) with varying amounts of treated oat hulls, alfalfa haylage, and corn silage as forage (65%). Treatments were 0 (control), 17.2 (low), 34.5 (medium), and 52.1% (high) treated oat hulls in the diet. Dry matter intake was 24.6, 27.1, 27.7, and 26.3 kg/d for the control, low, medium, and high treatments, respectively. Apparent digestibilities of DM, OM, and ADF were not affected by diet, but NDF and CP digestibilities were increased 15.6 and 6.9 percentage units, respectively, by feeding the largest amount of treated oat hulls compared with the control. Yields of milk, 4% FCM, and milk fat, protein, and SNF were highest for the diets that contained low and medium treated oat hulls. There were decreases in milk protein percentage (from 3.19 to 3.07%) and a trend towards increased milk fat percentage (from 3.53 to 3.63%) as the amount of treated oat hulls increased. Cows fed larger amounts of treated oat hulls had lower ruminal concentrations of total VFA with greater acetate:propionate ratios. Cows fed diets containing treated oat hulls had greater DM intakes and yields of 4% FCM and milk fat compared with those fed the control diet containing traditional forage sources.