Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5A8.
KWS Cereals USA, LLC, Champaign, IL 61822, USA.
J Anim Sci. 2024 Jan 3;102. doi: 10.1093/jas/skae211.
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.
本研究旨在评估增加干碾压杂交黑麦（HR）作为干碾压大麦粒（DRB）替代物对育肥牛采食量、瘤胃发酵以及养分消化部位和程度的影响。8 头荷斯坦杂交小公牛通过重复 4×4 拉丁方设计进行了瘤胃和十二指肠插管，每个周期包括 15 天的饮食适应期和 6 天的数据和样本收集期。日粮处理包括以干物质（DM）为基础的基础日粮，其中含有 10.00%的干草、85.21%的 DRB、4.51%的维生素和矿物质补充剂以及 0.28%的尿素。杂交黑麦粒替代了 33%、67%或 100%的 DRB。在每个时期的第 18 至 21 天收集饲料原料、饲料剩余物、瘤胃 pH 值、瘤胃液、十二指肠食糜和粪便样本。使用 SAS 9.4 的 Proc Glimmix 程序（SAS 研究所，Cary，NC）分析数据，以评估 HR 含量增加的线性、二次和三次效应。随着 HR 含量的增加作为 DRB 的替代品，DM 摄入量呈线性下降（P＜0.01），平均瘤胃 pH 值呈线性下降（P＜0.01），并且 pH 值＜5.5 的持续时间（P＜0.01）和面积（P=0.02）增加。HR 含量增加对瘤胃液中总短链脂肪酸和乳酸浓度没有影响。同样，HR 含量对乙酸和丁酸的摩尔比例没有影响。丙酸受 HR 含量的立方影响（P=0.02）。瘤胃无灰中性洗涤纤维（aNDFom）消化率随 HR 含量的增加呈线性增加（P=0.03），但瘤胃淀粉消化率平均为 71.1%（SEM=3.611），没有影响。随着 HR 含量的增加，肠道 DM 消化率呈线性增加（十二指肠流量的%；P=0.03），肠道有机物消化率呈线性增加趋势（P=0.08），肠道 aNDFom 消化率呈二次影响趋势（P=0.07）。随着杂交黑麦含量的增加，肠道 DM、有机物、粗蛋白、aNDFom 和淀粉消化率呈线性增加（P≤0.05）。此外，随着 HR 含量的增加，GE 消化率呈线性增加（P＜0.01），DE 浓度呈线性增加（P＜0.01）。在育肥日粮中增加 HR 粒作为 DRB 的替代物会降低 DMI，并增加低瘤胃 pH 值的风险，这可能与更高的可消化能量浓度有关，而更高的可消化能量浓度可能来自更高的 DM、OM、aNDFom 和淀粉消化率。
