Cooper R J, Milton C T, Klopfenstein T J, Scott T L, Wilson C B, Mass R A
Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA.
J Anim Sci. 2002 Mar;80(3):797-804. doi: 10.2527/2002.803797x.
Six ruminally and duodenally cannulated yearling steers (523 kg) were used in a replicated 3 x 3 Latin square design experiment to study the effects of corn processing on nutrient digestion, bacterial CP production, and ruminal fermentation. Dietary treatments consisted of 90% concentrate diets that were based on dry-rolled (DRC), high-moisture (HMC), or steam-flaked (SFC) corn. Each diet contained 2.0% urea (DM basis) as the sole source of supplemental nitrogen. Each period lasted 17 d, with d 1 through 14 for diet adaptation and d 15 through 17 for fecal, duodenal, and ruminal sampling. Dry matter and OM intakes were similar for DRC and SFC but were approximately 15% higher (P < 0.05) for HMC. True ruminal OM digestibilities were 18 and 10% greater (P < 0.05) for HMC than for DRC or SFC, respectively. Ruminal starch digestibilities were similar between HMC and SFC and were approximately 19% greater (P < 0.05) than DRC. Postruminal OM digestibility was similar among treatments; however, postruminal starch digestibility was 15% greater (P < 0.05) for SFC than for DRC or HMC, which were similar. Total-tract DM and OM digestibilities were similar between HMC and SFC and were 4% greater (P < 0.05) than DRC. Likewise, total-tract starch digestibilities were similar between HMC and SFC and were 3% greater (P < 0.05) than DRC. Bacterial CP flow to the duodenum was 29% greater (P < 0.05) for HMC than for DRC or SFC, which were similar. Bacterial N efficiencies were similar among treatments. Based on bacterial CP flow from the rumen, we estimate that dietary DIP requirements are approximately 12% higher for HMC-based diets than for DRC or SFC-based diets, which were similar.
选用6头装有瘤胃和十二指肠瘘管的一岁公牛（体重523千克），采用重复3×3拉丁方设计试验，研究玉米加工方式对营养物质消化、细菌粗蛋白产生及瘤胃发酵的影响。日粮处理包括以干碾压（DRC）、高水分（HMC）或蒸汽压片（SFC）玉米为基础的90%精料日粮。每种日粮含有2.0%的尿素（以干物质计）作为补充氮的唯一来源。每个试验期持续17天，第1至14天用于日粮适应，第15至17天用于粪便、十二指肠和瘤胃采样。DRC和SFC的干物质和有机物摄入量相似，但HMC的摄入量高出约15%（P<0.05）。HMC的瘤胃真有机物消化率分别比DRC或SFC高18%和10%（P<0.05）。HMC和SFC之间的瘤胃淀粉消化率相似，比DRC高约19%（P<0.05）。各处理间瘤胃后有机物消化率相似；然而，SFC的瘤胃后淀粉消化率比DRC或HMC高15%（P<0.05），DRC和HMC相似。HMC和SFC之间的全消化道干物质和有机物消化率相似，比DRC高4%（P<0.05）。同样，HMC和SFC之间的全消化道淀粉消化率相似，比DRC高3%（P<0.05）。HMC流向十二指肠的细菌粗蛋白流量比DRC或SFC高29%（P<0.05），DRC和SFC相似。各处理间细菌氮效率相似。根据瘤胃细菌粗蛋白流量估计，以HMC为基础的日粮的日粮可消化不可降解蛋白需求量比以DRC或SFC为基础的日粮高约12%，DRC和SFC相似。
