Department of Animal Science, University of California, Davis 95616, USA.
J Anim Sci. 2013 Apr;91(4):1801-10. doi: 10.2527/jas.2012-5260. Epub 2013 Feb 13.
Two experiments were conducted to examine the effect of level of dried distillers grains plus solubles (DDGS) supplementation (0, 10, 20, and 30%; DM basis), replacing steam-flaked (SF) corn in finishing diets, on characteristics of digestion (Exp. 1) and growth performance (Exp. 2) in calf-fed Holstein steers. In Exp.1, 4 cannulated Holstein steers (349 ± 12 kg) were used to evaluate treatment effects on characteristics of digestion. Ruminal NDF digestion tended to increase (quadratic effect, P = 0.09) and ruminal OM digestion decreased (linear effect, P = 0.01) with DDGS substitution. There were no treatment effects on duodenal flow of microbial N (MN). Substitution with DDGS increased (linear effect, P < 0.01) N flow to the small intestine. The undegradable intake protein (UIP) value of DDGS was 35%. Postruminal digestion of OM (linear effect, P = 0.04) and fatty acids (linear effect, P = 0.03) and total tract digestion of OM and GE decreased (linear effect, P < 0.03) with increasing level of DDGS substitution. Substitution with DDGS did not affect (P = 0.80) ruminal pH but increased (linear effect, P = 0.01) acetate:propionate molar ratio. In Exp.2, 144 Holsteins steer (112 ± 6 kg) were used in a 305-d trial to evaluate treatment effects on growth performance and carcass characteristics. During the initial 126 d, DDGS substitution increased ADG (linear effect, P = 0.03), G:F (quadratic effect, P = 0.03), and dietary NE (quadratic effect, P = 0.02), maximal for both at 20% DDGS inclusion rate. Based on estimated indispensable AA supply to the small intestine as a percentage of requirements during the initial 126-d period, histidine was first limiting followed by methionine. During the final 179-d period and overall (305-d feeding period), treatment effects on ADG and G:F were small (P ≥ 0.22). Compared with the other treatments, HCW was greater (3.4; P = 0.03) at the 20% level of DDGS substitution. The NE value for DDGS in SF corn-based diets for the calf-fed Holstein are consistent with current tabular standards. Extra-caloric value of DDGS as a metabolizable AA source is apparent during the initial growing phase. The UIP value of DDGS used in this study (35%) was considerably less than current tabular estimates (52%; NRC, 2000).
进行了两项实验来研究在育肥日粮中用不同水平的干燥酒糟及其可溶物（DDGS）（0、10、20 和 30%，DM 基础）替代蒸汽压片（SF）玉米对犊牛饲养的荷斯坦公牛育肥牛的消化特性（实验 1）和生长性能（实验 2）的影响。在实验 1 中，使用 4 个瘤胃瘘管荷斯坦公牛（349 ± 12 kg）评估处理对消化特性的影响。随着 DDGS 替代量的增加，瘤胃 NDF 消化率呈上升趋势（二次效应，P = 0.09），瘤胃 OM 消化率下降（线性效应，P = 0.01）。微生物 N（MN）的十二指肠流量不受处理影响。DDGS 的替代增加了小肠中 N 的流量（线性效应，P < 0.01）。随着 DDGS 替代水平的增加，OM（线性效应，P = 0.04）和脂肪酸（线性效应，P = 0.03）的后肠道消化以及 OM 和 GE 的全肠道消化率下降（线性效应，P < 0.03）。DDGS 的替代不会影响（P = 0.80）瘤胃 pH，但增加了（线性效应，P = 0.01）乙酸：丙酸摩尔比。在实验 2 中，使用 144 头荷斯坦公牛（112 ± 6 kg）进行了 305 天的试验，以评估处理对生长性能和胴体特性的影响。在最初的 126 天，DDGS 的替代增加了 ADG（线性效应，P = 0.03）、G:F（二次效应，P = 0.03）和日粮 NE（二次效应，P = 0.02），在 20% DDGS 含量时达到最大值。基于最初 126 天期间小肠必需氨基酸供应量占需求量的百分比估计，组氨酸是第一个限制氨基酸，其次是蛋氨酸。在最后 179 天和整个（305 天饲养期），ADG 和 G:F 的处理效果较小（P ≥ 0.22）。与其他处理相比，20% DDGS 替代水平时 HCW 更大（3.4；P = 0.03）。犊牛饲养的荷斯坦用 SF 玉米基础日粮的 DDGS 的 NE 值与当前表格标准一致。DDGS 作为可代谢 AA 来源的额外热量值在初始生长阶段明显。本研究中使用的 DDGS 的 UIP 值（35%）明显低于当前表格估计值（52%；NRC，2000）。
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