Five ruminally cannulated heifers were used in an incomplete 6 × 6 Latin square design to determine the effects of cereal silage (barley vs. corn), cereal grain (barley vs. corn vs. a 50:50 blend of barley and corn), and their interaction (S × G) on dry matter intake, ruminal fermentation, total tract digestibility, nitrogen balance, and in situ degradation. Corn silage (CS) or barley silage (BS) was included at 8% of dietary dry matter (DM). Within each silage source, diets contained (DM basis) either dry-rolled barley (BG; 86%), dry-rolled corn (CG; 85%), or an equal blend of barley and corn (BLEND; 85%). Periods were 25 d, with 5 d of dietary transition, 13 d of dietary adaptation, and 7 d of data and sample collection. Samples collected included feed and refusals, total urine and feces, and ruminal fluid. All data were analyzed using the Mixed model of SAS with the fixed effects of silage, grain, and the S × G. Dry matter intake (P ≥ 0.19) and mean ruminal pH (P ≥ 0.096) were not affected by the silage, grain, or S × G. Total short-chain fatty acid concentrations were greater for BLEND than BG or CG (grain, P = 0.003) and for CS (silage, P = 0.009) relative to BS. The molar proportion of acetate was greater for BS-BG and BS-CG (S × G, P < 0.001), while molar proportion of propionate was greater for CS-BG (S × G, P < 0.001) relative to other silage and grain source combinations. Rumen ammonia-N concentration was greater for CG than BG, or BLEND (grain, P < 0.001), and greater for CS compared to BS (silage, P = 0.023). Apparent total tract digestibility of DM, organic matter, neutral detergent fiber, starch, and gross energy were greatest for BG (grain, P ≤ 0.035). Digestible energy content (Mcal/kg) was greater for BG (grain, P = 0.029) than CG and BLEND. Total nitrogen retention (g/d and % of intake) was greatest for CS-BG (S × G, P ≤ 0.033) relative to all other treatments. In situ degradation rates of DM, crude protein, and starch were greater for BG than CG (P ≤ 0.004). The potentially degradable fraction of DM, crude protein, and starch was greater for CG (P ≤ 0.031), while the undegradable fraction was greater for BG (P ≤ 0.046). For silage sources, CS had greater 24 h in situ DM digestibility (P = 0.009) and starch digestibility (24, 48, and 72 h incubations, P ≤ 0.034) relative to BS. Results suggest that while feeding a combination of CS and BG promotes propionate production and greater N retention; few other additive effects were observed.

中文翻译：

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饲喂大麦或玉米青贮饲料与干碾大麦、玉米或大麦和玉米混合谷物对肥育小母牛瘤胃发酵、总消化道消化率和氮平衡的影响。

在不完整的 6 × 6 拉丁方设计中使用五头瘤胃插管小母牛来确定谷物青贮饲料（大麦与玉米）、谷物（大麦与玉米与 50:50 大麦和玉米的混合物）和谷物青贮饲料（大麦与玉米）的影响，以及它们在干物质摄入、瘤胃发酵、全消化道消化率、氮平衡和原位降解方面的相互作用 (S × G)。玉米青贮饲料 (CS) 或大麦青贮饲料 (BS) 占日粮干物质 (DM) 的 8%。在每种青贮饲料来源中，日粮含有（DM 基础）干轧大麦（BG；86%）、干轧玉米（CG；85%）或大麦和玉米的等量混合物（BLEND；85%）。周期为 25 天，其中 5 天为饮食过渡期，13 天为饮食适应期，7 天为数据和样本收集期。收集的样品包括饲料和拒食物、总尿液和粪便以及瘤胃液。所有数据均使用 SAS 混合模型进行分析，其中青贮饲料、谷物和 S × G 具有固定效应。干物质摄入量 (P ≥ 0.19) 和平均瘤胃 pH (P ≥ 0.096) 不受青贮饲料、谷物的影响。或 S × G。相对于 BS，BLEND 的总短链脂肪酸浓度高于 BG 或 CG（谷物，P = 0.003），CS（青贮饲料，P = 0.009）。相对于其他青贮饲料和饲料，BS-BG 和 BS-CG 的乙酸盐摩尔比例较高（S × G，P < 0.001），而 CS-BG 的丙酸盐摩尔比例较高（S × G，P < 0.001）。粮源组合。CG 的瘤胃氨氮浓度高于 BG 或 BLEND（谷物，P < 0.001），CS 的瘤胃氨氮浓度高于 BS（青贮饲料，P = 0.023）。BG 的干物质、有机物、中性洗涤纤维、淀粉和总能的表观总消化道消化率最大（谷物，P ≤ 0.035）。BG（谷物，P = 0.029）的消化能含量（Mcal/kg）高于 CG 和 BLEND。相对于所有其他处理，CS-BG 的总氮保留（g/d 和摄入百分比）最大（S × G，P ≤ 0.033）。BG 的 DM、粗蛋白和淀粉的原位降解率高于 CG (P ≤ 0.004)。CG 中 DM、粗蛋白和淀粉的潜在可降解部分较大（P ≤ 0.031），而 BG 中不可降解部分较大（P ≤ 0.046）。对于青贮饲料来源，相对于 BS，CS 具有更高的 24 小时原位 DM 消化率（P = 0.009）和淀粉消化率（24、48 和 72 小时孵育，P ≤ 0.034）。结果表明，同时饲喂 CS 和 BG 可以促进丙酸盐的产生并提高氮的保留；几乎没有观察到其他附加效应。