Abstract：
The aim of this study was to explore the effect of replacing protein pellets with soybean grain in high-concentrate diets with or without the addition of silage, on the intake, digestibility, and rumen and blood parameters of feedlot cattle in tropical regions. Four cannulated, crossbred steers were used, 4.5 ± 0.5 years old, with an average weight of 685.55 ± 111.78 kg. The steers were distributed in a 4 × 4 Latin square, in a 2 × 2 factorial scheme (two sources of protein: protein pellets or whole soybean grain, with or without added dietary bulk). There was no effect (P ≥ 0.109) from the interaction between the source of protein and the addition of silage to the diet on dry matter (DM) and nutrient intake, or the digestibility (P ≥ 0.625) of DM or crude protein (CP). However, both factors affected (P ≤ 0.052) the intake of DM, neutral detergent fiber (NDF), and non-fiber carbohydrates (NFC), as well as the independent digestibility (P ≤ 0.099) of fat, NFC, total carbohydrates (TC), and total cholesterol concentration. There was an effect (P ≤ 0.053) from the interaction between the source of protein and the addition of silage to the diet on the digestibility of NDF and total digestible nutrients (TDN), as well as on the glycose concentration (P = 0.003). Blood parameters (i.e. protein, albumin, creatinine, triglycerides, aspartate aminotransferase (AST), and alanine aminotransferase (ALT)) were not affected (P ≥ 0.139) by the source of protein, the addition of silage, or their interaction. Lastly, including 150 g/kg silage DM in a high-grain diet, and using soybean grain as a source of protein in substitution of protein pellet could be a suitable nutritional strategy to ensure adequate DM and nutrient intake and digestibility, with no detrimental effects on rumen and blood parameters of feedlot cattle in the tropics.
摘要：
本研究的目的是探讨在添加或不添加青贮饲料的高浓缩日粮中，用大豆谷物代替蛋白质颗粒的效果。在摄入量上，消化率，热带地区饲养牛的瘤胃和血液参数。四个插管，使用了杂交牛，4.5±0.5岁，平均体重685.55±111.78公斤。牛轮分布在一个4×4的拉丁正方形中，在2×2阶乘方案中(蛋白质的两种来源：蛋白质颗粒或全大豆颗粒，有或没有添加膳食增量)。蛋白质来源和在日粮中添加青贮饲料对干物质（DM）和营养素摄入量的相互作用没有影响（P≥0.109），或DM或粗蛋白（CP）的消化率（P≥0.625）。然而,这两个因素都影响(P≤0.052)DM的摄入量，中性洗涤剂纤维（NDF），和非纤维碳水化合物（NFC），以及脂肪的独立消化率(P≤0.099)，NFC,总碳水化合物（TC），和总胆固醇浓度。有一个作用（P≤0.053）从蛋白质的来源和添加青贮饲料的饮食对NDF的消化率和总消化性营养素（TDN）之间的相互作用，以及对糖浓度的影响(P=0.003)。血液参数（即蛋白质，白蛋白,肌酐,甘油三酯，天冬氨酸转氨酶（AST），和丙氨酸氨基转移酶（ALT））不受蛋白质来源的影响（P≥0.139），添加青贮饲料，或他们的互动。最后,包括高谷物饮食中的150克/千克青贮DM，用大豆作为蛋白质来源替代蛋白质颗粒可能是一种合适的营养策略，以确保充足的DM和营养摄入和消化率，对热带地区饲养牛的瘤胃和血液参数没有不利影响。
