Department of Animal Science, University of Nebraska, Lincoln, Nebraska 68583, USA.
J Anim Sci. 2012 Jan;90(1):296-306. doi: 10.2527/jas.2009-2414. Epub 2011 Aug 19.
Two experiments using 96 steers each were conducted to evaluate the effect of corn wet distillers grains plus solubles (WDGS) concentration on steer performance, N loss, and P mass balance. Feeding WDGS as an energy source instead of protein may increase N release into the environment but also the amount of N removed in the manure. Calves (BW = 294 ± 33 kg) were fed 167 d from November to May (WIN), and yearlings (BW = 373 ± 24 kg) were fed 133 d from June to October (SUM). Treatments consisted of 0, 15, and 30% dietary inclusion of WDGS (DM basis) replacing corn (CON, 15WDGS, 30WDGS, respectively). Basal diets consisted of high-moisture and dry-rolled corn fed at a 1:1 ratio, 7.5% alfalfa hay, 5% molasses, and 5% supplement (DM basis). The CON and 15WDGS diets were formulated to meet MP requirements, and 30WDGS exceeded MP requirements. Dry matter intake, ADG, and HCW increased linearly (P < 0.05) with WDGS concentration in the WIN, whereas DMI and ADG increased linearly (P < 0.10) in the SUM. Efficiency of BW gain was not different (P > 0.10) among treatments in either experiment. Nitrogen and P intake increased linearly (P < 0.01) with WDGS concentration in both experiments. Calculated retention of N and P increased linearly (P ≤ 0.05) with WDGS concentration in the WIN but not in the SUM (P > 0.10). Calculated excretion of N and P increased linearly (P < 0.01) with WDGS concentration in both experiments. Amount of N removed in the manure was not different (P = 0.26) among treatments in the WIN but increased linearly (P = 0.05) with WDGS concentration in the SUM. Amount of P and OM removed increased linearly (P ≤ 0.05) with WDGS concentration in both experiments. Amount of N lost (kg/steer) increased linearly (P < 0.05) with WDGS concentration in both experiments. Expressed as a percentage of N excretion, N volatilization rate (amount of N lost divided by N excretion) was not different (P > 0.30) among treatments and averaged 68.3 and 77.0 in the WIN and SUM, respectively. More N volatilized when WDGS were fed, but not all of the additional N excreted was volatilized. Regressing the amount of OM on the pen surface against manure N, 98% of the variability for manure N in the WIN and 92% in the SUM was accounted for. Feeding WDGS increased the total amount of N lost to volatilization; however, not all of the additional N excreted was lost because of an increase in the proportion of manure OM.
进行了两项实验，每个实验使用 96 头育肥牛，评估玉米湿酒糟及其可溶性物（WDGS）浓度对育肥牛性能、氮损失和磷质量平衡的影响。将 WDGS 用作能量来源而不是蛋白质，可能会增加氮向环境中的释放，但也会增加粪便中氮的去除量。犊牛（BW=294±33kg）从 11 月到 5 月（WIN）饲养 167 天，青年牛（BW=373±24kg）从 6 月到 10 月（SUM）饲养 133 天。处理包括 WDGS 日粮中 0%、15%和 30%的饲粮添加（DM 基础），分别替代玉米（CON、15WDGS、30WDGS）。基础日粮由高水分和干压玉米以 1:1 的比例组成，7.5%苜蓿干草，5%糖蜜和 5%补充料（DM 基础）。CON 和 15WDGS 日粮的配制满足了 MP 需求，而 30WDGS 超过了 MP 需求。在 WIN 中，干物质采食量、ADG 和 HCW 随 WDGS 浓度呈线性增加（P<0.05），而 DMI 和 ADG 在 SUM 中呈线性增加（P<0.10）。在两个实验中，BW 增重效率在处理之间没有差异（P>0.10）。氮和磷摄入量随 WDGS 浓度在两个实验中呈线性增加（P<0.01）。在 WIN 中，氮和磷的保留量随 WDGS 浓度呈线性增加（P≤0.05），但在 SUM 中没有（P>0.10）。氮和磷的排泄量随 WDGS 浓度在两个实验中呈线性增加（P<0.01）。在 WIN 中，粪便中去除的氮量在处理之间没有差异（P=0.26），但在 SUM 中随 WDGS 浓度呈线性增加（P=0.05）。在两个实验中，磷和 OM 的去除量随 WDGS 浓度呈线性增加（P≤0.05）。氮损失量（每头育肥牛）随 WDGS 浓度在两个实验中呈线性增加（P<0.05）。以氮排泄量的百分比表示，氮挥发率（氮损失量除以氮排泄量）在处理之间没有差异（P>0.30），分别为 WIN 中的 68.3%和 SUM 中的 77.0%。当 WDGS 被饲喂时，更多的氮挥发，但不是所有额外排泄的氮都挥发了。将每栏表面的 OM 与粪便氮回归，WIN 中 98%的粪便氮和 SUM 中 92%的粪便氮可归因于该回归。饲喂 WDGS 增加了氮向挥发的总损失量；然而，由于粪便 OM 比例的增加，并非所有额外排泄的氮都丢失了。
