To evaluate the effect of soy-hulls (SH) inclusion in a ground corn-based diet with either distillers dry grains with solubles (DDGS) or soybean meal (SBM) as the protein source (PS), on growth and carcass characteristics of feedlot cattle offered free-access hay; one-hundred and nineteen crossbreed steers (initial BW 566 ± 42kg) were blocked by weight, randomly assigned to 8 pens, and fed for 104 ± 10d. Four dietary treatments were evaluated: 1) DDGS without SH inclusion, 2) DDGS and high inclusion of SH, 3) SBM and low inclusion of SH, and 4) SBM and high inclusion of SH. Diets were formulated to be isonitrogenous. Grass-hay was offered ad-libitum and separate from the concentrates in a different bunk (GrowSafe system). Data was analyzed as a 2×2 factorial considering the fixed effects of treatments and their interaction, and the random effects of block and steer within block. For gain to feed and kidney-pelvic-heart fat (KPH), an interaction occurred (P ≤ 0.10) between PS and SH inclusion (Table 1 and 2, respectively). With greater inclusion of SH, feed efficiencies of steers fed SBM improved compared with feed efficiencies of steers fed DDGS. Steers fed SBM and high SH had the lower KPH content. Feeding SBM increased (P = 0.05) final body weight, tended to increase (P = 0.06) the average daily gain, and decreased (P = 0.05) hay intake compared with steers fed DDGS (Table 1). No differences were observed (P ≥ 0.14) in carcass characteristics between PS and SH inclusion, except for backfat thickness which increased (P = 0.03) with lower SH inclusions (Table 2). These data suggest that opting for SBM as an alternative of DDGS as the protein source of ground corn-based diets, could conceivably enhance the finishing performance of feedlot steers regardless of the SH inclusion levels, and improve feed efficiency with greater levels of dietary SH.

中文翻译：

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PSIV-3 蛋白源和大豆壳在饲养场牛饲喂自由选择干草的育肥日粮中对性能和胴体特征的影响

评估在以可溶物干粮 (DDGS) 或豆粕 (SBM) 作为蛋白质源 (PS) 的磨碎玉米日粮中添加大豆壳 (SH) 对饲养场生长和胴体特性的影响牛免费提供干草；119 头杂交肉牛（初始体重 566 ± 42 公斤）按体重分块，随机分配到 8 个栏，饲养 104 ± 10 天。对四种日粮处理进行了评估：1) DDGS 不添加 SH，2) DDGS 和 SH 高添加，3) SBM 和 SH 低添加，4) SBM 和 SH 高添加。日粮被配制成等氮。草干草是随意提供的，并与不同铺位的浓缩物分开（GrowSafe 系统）。考虑到治疗的固定效应及其相互作用，数据被分析为 2×2 因子，以及块内转向的随机效应。对于饲料增益和肾-盆腔-心脏脂肪 (KPH)，PS 和 SH 包含之间发生了相互作用 (P ≤ 0.10)（分别为表 1 和表 2）。与饲喂 DDGS 的肉牛相比，随着 SH 含量的增加，饲喂 SBM 的肉牛的饲料效率有所提高。饲喂 SBM 和高 SH 的公牛的 KPH 含量较低。与饲喂 DDGS 的公牛相比，饲喂 SBM 增加 (P = 0.05) 最终体重，倾向于增加 (P = 0.06) 平均日增重，并减少 (P = 0.05) 干草摄入量（表 1）。PS 和 SH 夹杂物之间的胴体特征没有观察到差异 (P ≥ 0.14)，除了背膘厚度随着 SH 夹杂物的减少而增加 (P = 0.03)（表 2）。