de Melo Amaral Paloma, de Campos Valadares Filho Sebastião, Detmann Edenio, Santos Stefanie Alvarenga, Prados Laura Franco, Silva Mariz Lays Débora, Alves Lyvian Cardoso, Menezes Ana Clara Baião, Villadiego Faider Alberto Castaño, Novaes Marco Aurélio Schiavo, de Sales Silva Flávia Adriane
Trop Anim Health Prod. 2014 Feb;46(2):419-26. doi: 10.1007/s11250-013-0507-z. Epub 2013 Nov 15.
Beef cattle (24) with an average initial body weight of 417 ± 54 kg were assigned in a 2 × 2 factorial design with six repetitions. The factors studied were two levels of CP: 11 (low CP) or 13 % (high CP) in the initial feedlot phase (days 1 - 36) and in the final phase (days 37 - 72). After 36 days, half of the bulls fed with each level of CP were selected to reverse the CP level. No interaction was observed (P > 0.05) between the level of protein in the initial and final phases on the intake of the nutrients evaluated. There was no effect (P > 0.05) of the protein levels in the initial and final phases on intake of dry matter, organic matter, CP, non-fiber carbohydrates, and total digestible nutrients. No differences were observed among treatments (P > 0.05) for average daily gain (X = 1.99 kg/day) and carcass traits. We conclude that it is possible to feed Holstein-Zebu crossed bulls with an average daily gain of approximately 2 kg using a fixed level of 11 % CP during the entire feedlot period, and this diet is economically viable and environmentally sound.
24头平均初始体重为417±54千克的肉牛，按照2×2析因设计分配，每组6个重复。研究的因素为粗蛋白（CP）的两个水平：在育肥前期（第1天至36天）和后期（第37天至72天），分别为11%（低CP）或13%（高CP）。36天后，从每组CP水平的公牛中选取一半，反转CP水平。在初始和最终阶段的蛋白质水平之间，未观察到（P>0.05）对所评估营养素摄入量的交互作用。初始和最终阶段的蛋白质水平对干物质、有机物、CP、非纤维碳水化合物和总可消化营养素的摄入量均无影响（P>0.05）。各处理间在平均日增重（X=1.99千克/天）和胴体性状方面未观察到差异（P>0.05）。我们得出结论，在整个育肥期使用11%CP的固定水平，有可能饲养出平均日增重约2千克的荷斯坦-瘤牛杂交公牛，并且这种日粮在经济上可行且对环境无害。
