The objective of this study was to evaluate the effects of the source of silage, cereal grain, and their interaction on growth performance, digestibility, and carcass characteristics of finishing beef cattle. Using a completely randomized design within an 89-d finishing study, 288 steers were randomly assigned to 1 of 24 pens (12 steers/pen) with average steer body weight (BW) within a pen of 464 kg ± 1.7 kg (mean ± SD). Diets were arranged in a 2 × 3 factorial with corn silage (CS) or barley silage (BS) included at 8% (dry matter [DM] basis). Within each silage source, diets contained dry-rolled barley grain (BG; 86% of DM), dry-rolled corn grain (CG; 85% of DM), or an equal blend of BG and CG (BCG; 85% of DM). Total tract digestibility of nutrients was estimated from fecal samples using near-infrared spectroscopy. Data were analyzed with pen as the experimental unit using the Mixed Model of SAS with the fixed effects of silage, grain, and the two-way interaction. Carcass and fecal kernel data were analyzed using GLIMMIX utilizing the same model. There were no interactions detected between silage and grain source. Feeding CG increased (P < 0.01) DM intake by 0.8 and 0.6 kg/d relative to BG and BCG, respectively. Gain-to-feed ratio was greater (P = 0.04) for BG (0.172 kg/kg) than CG (0.162 kg/kg) but did not differ from BCG (0.165 kg/kg). Furthermore, average daily gain (2.07 kg/d) and final body weight did not differ among treatments (P ≥ 0.25). Hot carcass weight (HCW) was 6.2 kg greater (372.2 vs. 366.0 kg; P < 0.01) and dressing percentage was 0.57 percentage units greater (59.53 vs. 58.96 %; P = 0.04) for steers fed CS than BS, respectively. There was no effect of dietary treatment on the severity of liver abscesses (P ≥ 0.20) with 72.0% of carcasses having clear livers, 24.4% with minor liver abscesses, and 3.6% with severe liver abscesses. Digestibility of DM, organic matter, crude protein, neutral detergent fiber, and starch were greater for BG (P < 0.01) than CG or BCG. As expected, grain source affected the appearance of grain kernels in the feces (P ≤ 0.04). Feeding CS silage increased the appearance of fractured corn kernels (P = 0.04), while feeding BS increased fiber appearance in the feces (P = 0.02). Current results indicate that when dry rolled, feeding BG resulted in improved performance and digestibility compared with CG and BCG. Even at low inclusion levels (8% of DM), CS resulted in improved carcass characteristics relative to BS.

中文翻译：

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当饲喂大麦、玉米或大麦和玉米混合物时，使用大麦或玉米青贮饲料对育肥肉牛的生长性能、养分利用率和胴体特性有影响。


本研究的目的是评估青贮饲料、谷物的来源及其相互作用对育肥肉牛生长性能、消化率和胴体特性的影响。在一项为期 89 天的育肥研究中，采用完全随机设计，将 288 头公牛随机分配到 24 个栏中的 1 个（12 头牛/栏），栏内的平均公牛体重 (BW) 为 464 kg ± 1.7 kg（平均值 ± SD） ）。日粮按 2 × 3 因子排列，其中玉米青贮饲料 (CS) 或大麦青贮饲料 (BS) 含量为 8%（以干物质 [DM] 为基础）。在每种青贮饲料来源中，日粮含有干碾大麦粒（BG；占 DM 的 86%）、干碾玉米粒（CG；占 DM 的 85%）或 BG 和 CG 的等量混合物（BCG；占 DM 的 85%） ）。使用近红外光谱法从粪便样本中估计营养素的总消化道消化率。以栏为实验单位，采用青贮饲料、谷物固定效应和双向交互作用的SAS混合模型对数据进行分析。使用 GLIMMIX 利用相同的模型分析屠体和粪便内核数据。青贮饲料和谷物来源之间没有检测到相互作用。相对于 BG 和 BCG，饲喂 CG 使 DM 摄入量分别增加 (P < 0.01) 0.8 和 0.6 kg/d。 BG (0.172 kg/kg) 的增重饲料比 (P = 0.04) 高于 CG (0.162 kg/kg)，但与 BCG (0.165 kg/kg) 没有差异。此外，不同治疗组的平均日增重（2.07 kg/d）和最终体重没有差异（P ≥ 0.25）。饲喂 CS 的公牛比饲喂 BS 的公牛的热胴体重量 (HCW) 多 6.2 kg（372.2 vs. 366.0 kg；P < 0.01），屠宰率高 0.57 个百分比单位（59.53 vs. 58.96 %；P = 0.04）。饮食治疗对肝脓肿的严重程度没有影响（P≥0.20）72。0%的尸体有清晰的肝脏，24.4%有轻微肝脓肿，3.6%有严重肝脓肿。 BG 的干物质、有机物、粗蛋白、中性洗涤纤维和淀粉的消化率高于 CG 或 BCG（P < 0.01）。正如预期的那样，谷物来源影响粪便中谷物颗粒的外观（P ≤ 0.04）。饲喂 CS 青贮饲料增加了破碎玉米粒的出现（P = 0.04），而饲喂 BS 则增加了粪便中纤维的出现（P = 0.02）。目前的结果表明，干轧时，与 CG 和 BCG 相比，饲喂 BG 可以提高性能和消化率。即使夹杂物含量较低（DM 的 8%），CS 也能比 BS 改善胴体特性。