摘要
Six studies were conducted to evaluate effects of corn silage harvest, hybrid, and concentration in growing and finishing diets. Experiment 1, evaluated corn silage DM (37 or 43%) and replacing corn grain with silage (15 or 45% of diet DM) in finishing diets. Experiment 2, evaluated corn silage DM (37 or 43%) and response to rumen undegradable protein (RUP) supplementation in growing diets. Experiment 3, evaluated nutrient digestibility of 37 or 43% DM corn silage at two different intakes. Experiment 4, 5, and 6 evaluated three corn silage hybrids: a standard hybrid control (CON), a brown midrib (bm3) hybrid (BM3), and an experimental bm3 hybrid (BM3-EXP) with a soft endosperm trait. Experiment 4 evaluated the three hybrids and concentration (15 or 45% of diet DM) in finishing diets, while Exp. 5 and 6, evaluated the same three silage hybrids in growing diets. In Exp. 1 with finishing cattle, as DM of silage increased from 37 to 43%, there were no differences (P ≥ 0.30) in DMI, ADG, or G:F. In Exp. 2 with growing cattle, as DM of silage increased from 37 to 43%, ADG and G:F were reduced (P ≤ 0.04). Increasing supplemental RUP in the diet increased (P ? 0.05) ending BW, ADG, and G:F linearly. In Exp. 1 and 4, as concentration of silage in the finishing diet increased from 15 to 45%, ADG and G:F decreased (P ≤ 0.04). In Exp 4, BMR-EXP had the greatest ADG and G:F at 15% silage. At 45% silage, both bm3 hybrids had greater (P ≤ 0.05) ADG than CON, but G:F was greatest for cattle fed BM3 (P<0.03). In Exp 5 with growing cattle, ending BW, DMI, and ADG were greater (P < 0.01) for steers fed the BM3 and BM3-EXP compared to the CON. In Exp. 6, steers fed both bm3 hybrids had greater (P < 0.01) NDF and ADF digestibility than the CON. Delayed silage harvest decreased performance in growing diets, but did not affect performance of finishing cattle. Silage hybrids containing the bm3 trait improved performance, and improvement was most evident with large concentrations of silage.
摘要译文
进行了六项研究，以评估玉米青贮饲料的收成，杂种以及在日粮和日粮中的浓度。实验1评估了玉米青贮饲料DM（37或43％），并用青贮饲料（日粮DM的15或45％）代替了玉米谷物。实验2评估了生长日粮中玉米青贮DM（37％或43％）以及对瘤胃不可降解蛋白（RUP）补充的反应。实验3评估了两种不同摄入量下37或43％DM玉米青贮饲料的养分消化率。实验4、5和6评价了三种玉米青贮杂种：标准杂种对照（CON），棕色中肋（bm3）杂种（BM3）和具有软胚乳特性的实验性bm3杂种（BM3-EXP）。实验4评估了三个杂种和精饲料中的浓度（日粮DM的15或45％），而实验4则为日粮。图5和图6评估了生长日粮中相同的三种青贮饲料杂种。在实验中1头育肥牛，由于青贮饲料的DM从37％增至43％，DMI，ADG或G：F没有差异（P≥0.30）。在实验中有2个生长的牛，随着DM青贮率从37％增加到43％，ADG和G：F降低（P≤0.04）。饮食中补充补充RUP增加（P？ 0.05）线性结束BW，ADG和G：F。在实验中从图1和图4可以看出，随着最终饲料中青贮饲料的浓度从15％增加到45％，ADG和G：F降低（P≤0.04）。在实验4中，BMR-EXP在15％的青贮饲料中具有最大的ADG和G：F。在青贮度为45％的情况下，两个bm3杂种的ADG均比CON大（P≤0.05），但饲喂BM3的牛的G：F最大（P <0.03）。在实验5中，随着牛的生长，与CON相比，饲喂BM3和BM3-EXP的公牛的最终体重，DMI和ADG更大（P <0.01）。在实验中从图6可以看出，饲喂两种bm3杂种的公牛的NDF和ADF消化率均高于CON。青贮饲料延迟收获会降低日粮的生长性能，但不会影响育肥牛的生长性能。含有bm3性状的青贮杂种提高了性能，并且在青贮浓度高的情况下改善最为明显。