The objective of this study was to evaluate effects of increasing the inclusion of dry-rolled hybrid rye (HR) as a replacement for dry-rolled barley grain (DRB) on feed intake, ruminal fermentation, and the site and extent of nutrient digestion for finishing cattle. Eight ruminally and duodenally cannulated Hereford-cross heifers were used in a replicated 4 × 4 Latin square design with 21-d periods including 15 d of dietary adaptation and 6 d of data and sample collection. Dietary treatments included a control diet with 10.00% grass hay, 85.21% DRB, 4.51% of a vitamin and mineral supplement, and 0.28% of urea on a dry matter (DM) basis. Hybrid rye grain replaced 33%, 67%, or 100% of the DRB. Feed ingredients, feed refusals, ruminal pH, ruminal fluid, duodenal digesta, and fecal samples were collected from days 18 to 21 in each period. Data were analyzed using the Proc Glimmix procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) to evaluate the linear, quadratic, and cubic effects of increasing HR inclusion. Increasing HR inclusion as a substitute for DRB linearly decreased (P < 0.01) DM intake, linearly decreased mean ruminal pH (P < 0.01), and increased the duration (P < 0.01) and area (P = 0.02) that ruminal pH was < 5.5. There were no effects of HR inclusion on total short chain fatty acid and lactic acid concentrations in ruminal fluid. Likewise, the molar proportions of acetate and butyrate were not affected by HR inclusion. Propionate was cubically affected by HR inclusion (P = 0.02). Ruminal ash-free neutral detergent fiber (aNDFom) digestibility linearly increased (P = 0.03) with increasing HR, but there was no effect on ruminal starch digestibility averaging 71.1% (SEM = 3.611). Increasing HR inclusion linearly increased intestinal DM digestibility (% of flow to the duodenum; P = 0.03), tended to linearly increase intestinal digestibility of organic matter (P = 0.08), and tended to quadratically affect intestinal digestibility of aNDFom (P = 0.07). Increasing hybrid rye linearly increased apparent total tract DM, organic matter, crude protein, aNDFom, and starch digestibility (P ≤ 0.05). In addition, increasing HR inclusion linearly increased GE digestibility (P < 0.01) and the DE concentration (P < 0.01). Increasing the inclusion rate of HR grain as a substitute for DRB in finishing diets decreased DMI and increased risk for low ruminal pH, which may be influenced by greater digestible energy concentration arising from greater DM, OM, aNDFom, and starch digestibility.

中文翻译：

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饲喂杂交黑麦谷物作为大麦粒的替代品对育肥肉小母牛干物质摄入量、瘤胃发酵以及营养物质消化部位和程度的影响


本研究的目的是评估增加添加干轧杂交黑麦 （HR） 作为干轧大麦粒 （DRB） 的替代品对采食量、瘤胃发酵以及育肥牛营养消化部位和程度的影响。8 头反刍和十二指肠插管的赫里福德杂交小母牛用于复制的 4 × 4 拉丁方形设计，具有 21 d 周期，包括 15 d 的饮食适应和 6 d 的数据和样本收集。饮食处理包括对照饮食，其中 10.00% 草干草、85.21% DRB、4.51% 维生素和矿物质补充剂以及 0.28% 的尿素（以干物质 （DM） 为基础。杂交黑麦谷物取代了 DRB 的 33%、67% 或 100%。在每个时期的第 18 至 21 天收集饲料成分、饲料拒绝、瘤胃 pH 值、瘤胃液、十二指肠消化液和粪便样本。使用 SAS 9.4 （SAS Inst. Inc.， Cary， NC） 的 Proc Glimmix 程序分析数据，以评估增加 HR 纳入的线性、二次和三次效应。增加 HR 纳入作为 DRB 的替代品线性降低 （P < 0.01） DM 摄入量，线性降低平均瘤胃 pH 值 （P < 0.01），并增加瘤胃 pH 值为 < 5.5 的持续时间 （P < 0.01） 和面积 （P = 0.02）。HR 包埋对瘤胃液中总短链脂肪酸和乳酸浓度没有影响。同样，乙酸盐和丁酸盐的摩尔比例不受 HR 包涵的影响。丙酸盐受 HR 纳入的立方影响 （P = 0.02）。瘤胃无灰分中性洗涤纤维 （aNDFom） 消化率随着 HR 的增加而线性增加 （P = 0.03），但对瘤胃淀粉消化率没有影响，平均为 71.1% （SEM = 3.611）。 增加 HR 包含线性增加肠道 DM 消化率（流向十二指肠的流量百分比;P = 0.03），倾向于线性增加有机物的肠道消化率 （P = 0.08），并倾向于二次影响 aNDFom 的肠道消化率 （P = 0.07）。增加杂交黑麦线性增加表观总道 DM 、有机质、粗蛋白、aNDFom 和淀粉消化率 （P ≤ 0.05）。此外，增加 HR 夹杂物线性增加了 GE 消化率 （P < 0.01） 和 DE 浓度 （P < 0.01）。在育肥日粮中增加 HR 谷物作为 DRB 替代品的添加率降低了 DMI 并增加了低瘤胃 pH 值的风险，这可能是由于更高的 DM、OM、aNDFom 和淀粉消化率而产生的可消化能量浓度增加的影响。