Sugarcane and cactus cladodes plus urea: a new option for Girolando dairy heifers

This study was performed to identify the ideal amount of concentrate required for a diet based on cactus cladodes, sugarcane, and urea used to feed heifers. Twenty Girolando heifers (160 +/- 8.39 kg) were randomly distributed into four experimental treatments with 0, 0.40, 0.80, or 1.20 kg day(-1) of concentrate. The basal diet contained [on dry matter (DM) basis] 38.1% sugarcane, 56.5% cactus cladodes [Opuntia stricta (Haw). Haw], 0.5% common salt, 1.1% mineral mixture, and 3.8% urea plus ammonium sulfate. The concentrate contained [on DM basis] 87% corn meal and 13% soybean meal. The basal diet and the concentrate were formulated to provide 13% crude protein (CP). The intake of DM (4.34-4.96 kg day(-1)), organic matter (3.96-4.98 kg day(-1)), CP (0.57-0.64 kg day(-1)), non-fibrous carbohydrates (2.20-2.61 kg day(-1)), and metabolizable energy (10.3-12.4 Mcal day(-1)) increased linearly with concentrate amount. Final body weight (196-224 kg), total body weight gain (36.9-61.2 kg), and average daily body weight gain (0.51-0.85 kg day(-1)) increased linearly with concentrate amount. The nitrogen balance was positive and increased linearly (54.8-62.3 g day(-1)) with concentrate amount. Based on the data, we recommend supplying six-monthold Girolando heifers (160 kg body weight) 1.20 kg concentrate day(-1) added to a diet based on sugarcane and cactus cladodes plus urea for better productive and economic performance