Krause M, Beauchemin K A, Rode L M, Farr B I, Nørgaard P
Department of Animal Science and Animal Health, Royal Veterinary and Agricultural University, Frederiksberg C, Denmark.
J Anim Sci. 1998 Nov;76(11):2912-20. doi: 10.2527/1998.76112912x.
We conducted a study to determine the effects of treating barley grain with a fibrolytic enzyme mixture on chewing activities, ruminal fermentation, and total tract digestibility in cattle. We also investigated the potential benefits of using barley straw rather than barley silage as a roughage source in high-grain diets for feedlot cattle. Steers were given ad libitum access to one of four diets that consisted of 95% barley-based concentrate and 5% forage (DM basis). The concentrate was either control or enzyme-treated, and the forage was either barley silage or barley straw. Applying the enzyme mixture onto the barley lowered the concentrations of dietary ADF and NDF. However, it is not certain when this fiber hydrolysis occurred relative to feed consumption because the fiber analyses were conducted after the study was completed. Enzyme treatment of barley increased total tract dietary ADF digestibility by 28% (P<.05). Acetate-to-propionate ratio tended to decrease, which suggests that enzymes may have increased ruminal starch digestion as a result of enhanced digestion of barley hulls. Replacing silage with straw increased ADF intake (P<.05) and resulted in 1-h/d increase in rumination time (P<.05). Even though there was no effect of diet on ruminal pH, replacing silage with straw increased ruminal acetate, as a percentage of total VFA, and total tract ADF digestion (P<.01). This study demonstrates that using a fibrolytic enzyme mixture in high-grain diets that contain mainly barley grain can improve fiber digestion and grain utilization, but the mode of action is unclear. Straw can be used rather than silage to increase the effective fiber content of a high-grain feedlot diet.
我们开展了一项研究，以确定用纤维分解酶混合物处理大麦籽粒对牛咀嚼活动、瘤胃发酵及全消化道消化率的影响。我们还研究了在育肥牛的高谷物日粮中，使用大麦秸秆而非大麦青贮料作为粗饲料来源的潜在益处。给阉牛随意提供四种日粮中的一种，这些日粮由95%的大麦型精料和5%的草料（干物质基础）组成。精料要么是对照日粮，要么是经酶处理的日粮，草料要么是大麦青贮料，要么是大麦秸秆。将酶混合物应用于大麦可降低日粮中酸性洗涤纤维（ADF）和中性洗涤纤维（NDF）的浓度。然而，由于纤维分析是在研究结束后进行的，所以不确定这种纤维水解相对于采食饲料而言是何时发生的。对大麦进行酶处理使全消化道日粮ADF消化率提高了28%（P<0.05）。乙酸与丙酸的比例有降低趋势，这表明由于大麦外壳消化增强，酶可能提高了瘤胃淀粉消化率。用秸秆替代青贮料增加了ADF摄入量（P<0.05），并使反刍时间每天增加1小时（P<0.05）。尽管日粮对瘤胃pH值没有影响，但用秸秆替代青贮料增加了瘤胃乙酸占总挥发性脂肪酸的百分比以及全消化道ADF消化率（P<0.01）。本研究表明，在主要含大麦籽粒的高谷物日粮中使用纤维分解酶混合物可改善纤维消化和谷物利用，但作用方式尚不清楚。可以使用秸秆而非青贮料来提高高谷物育肥牛日粮的有效纤维含量。
