Effects of feeding different levels of dietary fiber through the addition of corn stover on nutrient utilization of dairy heifers precision-fed high and low concentrate diets.
Effects of feeding different levels of dietary fiber through the addition of corn stover on nutrient utilization of dairy heifers precision-fed high and low concentrate diets.
复制标题
添加玉米秸秆饲喂不同水平膳食纤维对精饲高低精料奶牛营养利用的影响
DOI：
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发表时间：
2011
影响因子：
3.5
通讯作者：
A. Heinrichs
中科院分区：
文献类型：
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作者：
G. Lascano;A. Heinrichs
本试验旨在评价精饲母牛高精料（HC）和低精料（LC）饲粮中以低品质饲料替代玉米青贮（CS）作为玉米秸秆（CST）调控饲粮纤维的效果。选取8头体重（335.6±7.41 kg）的荷斯坦小母牛，随机分为HC（20%饲料）和LC（80%饲料）2个精料水平，按饲料类型顺序依次为：0%玉米秸秆（CST）、100%玉米青贮（CS）；成本20%，成本80%；成本40%，成本60%；和60% CST， 40% CS]在浓缩水平内，根据分裂图，4 × 4拉丁方形设计（21 d周期）。饲喂HC的小母牛全道干物质表观消化率（DMD）较高。通过增加饲粮中CST的添加量来提高纤维水平，DMD和有机物消化率呈线性降低。与HC饲粮相比，LC饲粮对中性洗涤纤维（NDF）的消化率较高，对酸性洗涤纤维（ADF）的消化率较低。用20%的CST替代CS， NDF和ADF消化率最高。氮的消化率无显著差异，但氮的保留率在HC组增加，在LC组呈二次曲线下降。饲喂HC日粮的小母牛粪量减少，而CST使这些参数线性增加。hc喂养的小母牛的尿量往往更高，通过添加CST增加膳食纤维往往会减少尿量。这种水排泄的变化导致了相似的粪便总产量。总嘌呤衍生物的排泄量在不同处理之间没有差异，但与添加CST相互作用，导致hc喂养的母牛十二指肠微生物蛋白流量呈线性增加，而LC饲粮随着CST的增加呈线性减少。综上所述，通过CST增加饲粮纤维可线性降低DMD和有机物消化率，而在HC和LC饲粮中添加20% CST时NDF和ADF消化率最高。在HC和LC饲粮中，微生物蛋白合成分别随CST添加量的增加而线性增加和减少。在HC和LC饲粮中，随CST添加量的增加，氮保留量分别呈二次曲线上升和下降。总粪便排泄量在HC和LC饲粮之间没有差异。
The objective of this experiment was to assess the effects of manipulating dietary fiber by replacing corn silage (CS) with lower quality forage as corn stover (CST) when used in high concentrate (HC) and low concentrate (LC) diets for precision-fed dairy heifers. Eight Holstein heifers (335.6 ± 7.41 kg of body weight) were randomly assigned to 2 levels of concentrate: HC (20% forage) and LC (80% forage), and to a forage type sequence [0% of forage as corn stover (CST), 100% corn silage (CS); 20% CST, 80% CS; 40% CST, 60% CS; and 60% CST, 40% CS] within concentrate level administered according to a split-plot, 4 × 4 Latin square design (21-d periods). Heifers fed HC had higher apparent total-tract dry matter digestibility (DMD). Increasing the fiber level by increasing the amount of CST in the diet resulted in a linear decrease of DMD and organic matter digestibility. Heifers fed LC diets had higher neutral detergent fiber (NDF) digestibility and tended to have lower acid detergent fiber (ADF) digestibility than those fed HC diets. Substituting CS with 20% CST resulted in the highest NDF and ADF digestibilities. Digestibility of N was not different, but N retention increased for HC and decreased quadratically for LC diets. Heifers fed HC diets decreased fecal output, and CST linearly increased these parameters. Urine volume tended to be higher for HC-fed heifers, and increasing dietary fiber through CST inclusion tended to decrease urine output. This shift in water excretion resulted in similar total manure output. Total purine derivative excretion did not differ between treatments, but interacted with CST addition, resulting in a linear increase in microbial protein flow to the duodenum in HC-fed heifers and in a linear decrease in LC diets as CST increased. In conclusion, increasing dietary fiber through CST decreased DMD and organic matter digestibility linearly, whereas NDF and ADF digestibility were maximized when 20% CST was added to HC and LC diets. Microbial protein synthesis increased and decreased linearly with CST addition in HC and LC diets, respectively. Retention of N increased and decreased quadratically with CST addition in HC and LC diets, respectively. Total manure excretion was not different between HC or LC diets.