Performance and economic evaluation of feedlot cattle fed sugarcane tops

摘要

The objective was to evaluate the productive and economic performances of 32 Nellore bulls kept in a feedlot provided with different levels of sugarcane tops as a substitute for sugarcane, in diets containing 33% of roughage. Four levels of substitution were evaluated: T0 = no addition of sugarcane tops; T33 = 33% substitution; T67 = 67% substitution; and T100 = total substitution of sugarcane by sugarcane tops. Shrunk body weight was measured at the beginning and end of the experiment. Dry matter, crude protein (CP), neutral detergent fiber (NDF), ether extract (EE) and non-fibrous carbohydrate (NFC) intakes, total body weight gain, average daily gain, and feed conversion ratio were evaluated. In addition, economic parameters (total revenue, effective operating cost, total operating cost, gross margin, and net margin) were assessed, and indexes previously reported in the literature were utilized in the determination of feedlot costs. The CP, NDF, EE, and NFC intakes were different (P < 0.013) among treatments. The other parameters did not differ (P > 0.38) among treatments. All treatments presented a positive net margin, which represents that the utilization of any level of sugarcane tops is viable. However, the 33% substitution provided the greatest numerical net margin value. In conclusion, partial or total substitution of sugarcane by sugarcane tops in diets containing 33% of roughage does not affect the performance of feedlot young bulls; moreover, it is recommended to substitute sugarcane by sugarcane tops at 33% since, at this level, a numerical reduction of production costs and greater numerical gross and net margins are obtained when compared with other levels of substitution.