This trial was conducted to investigate the replacement of soybean meal with a mixture of urea plus cassava scrapings on nutrient intake, digestibility, and production of crossbred lactating cows fed diets containing forage cactus (Opuntia ficus indica, Mill), sorghum silage, and concentrate. Eight crossbred holstein:zebu cows averaging 60±30 days in milk and initial body weight (BW) of 491 kg were randomly assigned to two replicated 4 × 4 Latin squares and were fed diets with increasing levels of urea plus cassava scrapings: 0, 33, 67 or 100%. Replacing soybean meal with urea plus cassava scrapings linearly decreased the intakes of DM (kg, % BW and g/BW kg0.75), OM, CP, EE, NDF, and TC. However, the increasing dietary levels of urea plus cassava sacrapings did not affetc the intakes of NDF (% BW), ADF, NFC, and TDN. Apparent digestibilities of all nutrients showed significant quadratic effects with increasing urea plus cassava scrapings. Milk yield, milk yield corrected for 4.0% fat and milk fat yield all decreased linearly by 30, 20 and, 0.8 g/day, respectively, while fat content and feed efficiency, expressed as kg of 4.0% fat corrected milk/kg of DM, were not changed by decreasing soybean meal in the diet.
digestibility; intake; milk yield; non-protein-nitrogen (NNP); protein
