Replacement of wheat bran with spineless cactus (Opuntia ficus indica Mill cv Gigante) and urea in the diets of Holstein x Gyr heifers

摘要

The aim of this study was to evaluate the replacement effect of wheat bran with spineless cactus and urea in heifers. Twenty-four heifers with an average initial weight of 185 +/- 13 kg were used in this experiment. Four levels of spineless cactus corrected with urea and ammonium sulfate (9:1) were studied: 0, 33, 66, and 100 % replacement with wheat bran. Samples of feed, orts, and feces were analyzed to estimate the intake and digestibility of dry matter (DM) and nutrients. Indigestible neutral detergent fiber was used as an internal marker. The experiment was conducted in a completely randomized design. Dry matter, neutral detergent fiber, and total digestible nutrient intake demonstrated a quadratic effect (P < 0.05). Rumen degradable protein intake increased linearly (P < 0.05). The maximum DM digestibility was estimated to be 0.67 with a 43 % replacement. Crude protein and NDF digestibility increased linearly (P < 0.05). The total body weight gain and average daily gain decreased linearly with the replacement. Thus, it is practical to replace wheat bran with spineless cactus containing urea and ammonium sulfate up to 66 % in sugar cane-based diets