Harrelson F W, Luebbe M K, Meyer N F, Erickson G E, Klopfenstein T J, Jackson D S, Fithian W A
Department of Animal Science, University of Nebraska, Lincoln, NE 68583, USA.
J Anim Sci. 2009 Jul;87(7):2323-32. doi: 10.2527/jas.2008-1527. Epub 2009 Apr 9.
A finishing trial and a digestion trial were conducted to evaluate the effects of corn hybrid and processing method on nutrient digestibility, finishing performance, and carcass characteristics. A 2 x 5 factorial arrangement of treatments was used for both trials. Factors included 2 processing methods, dry-rolled (DRC) or high-moisture (HMC), and 5 commercially available corn hybrids. The finishing trial (Exp. 1) utilized 475 yearling steers (379 +/- 15 kg initial BW), stratified by BW into 2 blocks then assigned randomly to 1 of 60 pens (8 steers/pen). Treatments were assigned randomly to pens with 6 pens/treatment. Diets consisted of 67.5% corn (each hybrid processed as DRC or HMC), 20% wet corn gluten feed, 7.5% alfalfa hay, and 5% supplement. The digestion trial (Exp. 2) used 2 ruminally and duodenally fistulated Holstein steers (560 kg of BW) and the mobile bag technique. Bags were ruminally incubated for 22 h. For total tract digestibility, bags were subjected to a simulated abomasal pepsin digestion, inserted into the duodenum, and collected in the feces. No significant interactions between corn hybrid and processing method were observed in Exp. 1; therefore, only main effects are presented. Feeding HMC decreased (P < 0.01) DMI and increased (P < 0.01) G:F compared with cattle fed DRC. Hybrid tended to affect (P = 0.12) G:F, but did not affect (P > 0.36) any other variable. For Exp. 2, feeding HMC increased (P < 0.01) DM and starch digestibility compared with DRC, but to varying degrees depending on the hybrid. Correlating the results of the 2 trials across processing methods, strong relationships were observed between G:F and postruminal starch digestibility (r = 0.84) and total-tract starch digestibility (r = 0.73). When evaluated within processing method, these relationships weakened and were not significant. The results of these trials indicate that processing method had a larger effect on performance and digestibility than hybrid, and no interaction was observed between processing method and hybrid, suggesting hybrid effects were consistent across processing methods.
进行了育肥试验和消化试验，以评估玉米杂交种和加工方法对养分消化率、育肥性能和胴体特性的影响。两个试验均采用2×5析因处理设计。因素包括2种加工方法，即干碾压（DRC）或高水分（HMC），以及5个市售玉米杂交种。育肥试验（试验1）使用了475头一岁公牛（初始体重379±15千克），按体重分层为2个区组，然后随机分配到60个栏中的1个（每栏8头牛）。处理随机分配到栏，每个处理6栏。日粮由67.5%的玉米（每个杂交种加工为DRC或HMC）、20%的湿玉米麸质饲料、7.5%的苜蓿干草和5%的补充料组成。消化试验（试验2）使用了2头瘤胃和十二指肠造瘘的荷斯坦公牛（体重560千克）以及移动袋技术。袋子在瘤胃中培养22小时。对于全肠道消化率，袋子经过模拟皱胃胃蛋白酶消化，插入十二指肠，并在粪便中收集。试验1中未观察到玉米杂交种和加工方法之间的显著交互作用；因此，仅呈现主效应。与饲喂DRC的牛相比，饲喂HMC降低了（P<0.01）干物质采食量并提高了（P<0.01）料重比。杂交种倾向于影响（P = 0.12）料重比，但不影响（P>0.36）任何其他变量。对于试验2，与DRC相比，饲喂HMC提高了（P<0.01）干物质和淀粉消化率，但因杂交种不同而程度各异。将两种加工方法下两个试验的结果进行关联，发现料重比与瘤胃后淀粉消化率（r = 0.84）和全肠道淀粉消化率（r = 0.73）之间存在强相关性。在加工方法内进行评估时，这些相关性减弱且不显著。这些试验结果表明，加工方法对性能和消化率的影响大于杂交种，且未观察到加工方法与杂交种之间的交互作用，这表明杂交种效应在不同加工方法中是一致的。
