Eastern Oregon Agricultural Research Center, Oregon State University, Union, Oregon 97883, USA.
J Anim Sci. 2011 Dec;89(12):4142-50. doi: 10.2527/jas.2010-3653. Epub 2011 Aug 5.
Consecutive receiving studies were used to evaluate the replacement of starch (dry rolled corn; DRC) with a nonforage fiber source (soybean hulls; SBH) on performance, mineral, and blood metabolite status of newly arrived feedlot steer calves. Steers in yr 1 (Y1; 9 pens/diet, 8 to 10 animals/pen) and yr 2 (Y2; 6 pens/diet, 9 to 10 animals/pen) were blocked by weaning management, and then stratified by BW and randomly assigned to pens. Pens were randomly assigned to an oat silage-based diet containing starch (HS) from DRC or digestible fiber (HF) from SBH. Diets were formulated for 12% CP (DM basis) and to meet or exceed NRC (1996) nutrient requirements for Ca, P, and vitamins A and E. Mineral status was assessed in Y1 only via liver biopsies and serum samples collected on d 3 and 28. Mineral concentrations on d 28 were compared using d 3 concentrations as a covariate. Glucose, NEFA, and plasma urea N status were assessed in Y2 only via blood collections on d 0, 3, 7, 14, 28, and 59. Morbidity (<10%) and mortality rates were not different (P > 0.10) between treatments across years. Daily BW gain was similar (P > 0.10) between treatments both during the receiving period and cumulatively across years. Overall, feed intake was greater (P = 0.007) for steers fed HF compared with steers fed HS in Y1, but was not different in Y2 (P = 0.13). Steers consuming the HS diet tended (P = 0.07) to have better BW gain efficiency in Y1 only. Across years, BW gain efficiency and ADG were similar between treatments (P > 0.10), although DMI was greater for steers fed HF (P = 0.003). Based on 2 yr of performance, the calculated ME content of SBH was estimated at 92.5% of the ME value of DRC (2.74 vs. 2.96 Mcal/kg, respectively). Mineral concentrations on d 28 were similar (P > 0.10) for most minerals assayed. There was a steeper (P = 0.005) decline in hepatic Cu concentrations early in the feeding period for steers fed HF, resulting in decreased (P = 0.001) d 28 hepatic concentrations. Hepatic Mn was greater (P = 0.003) in steers fed HF on d 28 as a result of greater (P = 0.006) Mn accumulation during the initial 28 d on feed. Blood metabolites in Y2 (using d 0 values as a covariate) were similar (P > 0.10) across treatments, except for reduced (P = 0.025) plasma urea N concentrations on d 7 and greater (P = 0.050) NEFA concentrations on d 28 for steers fed HS. These studies indicate that the use of SBH in receiving diets can support BW gain similar to the use of DRC.
连续接受研究用于评估淀粉（干压玉米；DRC）与非饲料纤维源（豆壳；SBH）替代对新到达育肥场犊牛的性能、矿物质和血液代谢物状态的影响。在第 1 年（Y1；9 个饲槽/饮食，8-10 个动物/饲槽）和第 2 年（Y2；6 个饲槽/饮食，9-10 个动物/饲槽）中，根据断奶管理对牛进行分组，然后按体重和随机分配到饲槽。饲槽随机分配到以燕麦青贮为基础的饮食，其中含有 DRC 的淀粉（HS）或 SBH 的可消化纤维（HF）。日粮的蛋白质含量为 12%（干物质基础），并满足或超过 NRC（1996）对钙、磷和维生素 A 和 E 的营养需求。仅在 Y1 中通过肝脏活检和在第 3 天和第 28 天收集的血清样本评估矿物质状态。使用第 3 天的浓度作为协变量比较第 28 天的矿物质浓度。仅在 Y2 中通过在第 0、3、7、14、28 和 59 天收集血液样本评估葡萄糖、NEFA 和血浆尿素氮状态。在 Y1 中，死亡率（<10%）和死亡率在各处理组之间没有差异（P > 0.10）。在 Y1 中，与 HS 组相比，HF 组的每日体重增加相似（P > 0.10），但在 Y2 中没有差异（P = 0.13）。在 Y1 中，与 HS 组相比，食用 HF 组的采食量增加（P = 0.007）。在 Y1 中，仅 HF 组的体重增重效率较高（P = 0.07）。在整个研究期间，处理之间的体重增重效率和 ADG 相似（P > 0.10），尽管 HF 组的采食量较高（P = 0.003）。基于 2 年的性能，计算得出 SBH 的 ME 含量估计为 DRC 的 ME 值的 92.5%（分别为 2.74 和 2.96 Mcal/kg）。在 Y1 中，大多数测定的矿物质的第 28 天浓度相似（P > 0.10）。HF 组牛在早期喂养期间肝脏铜浓度下降更快（P = 0.005），导致第 28 天肝脏浓度降低（P = 0.001）。由于在最初的 28 天喂饲期间锰积累更多，HF 组牛的第 28 天肝脏锰浓度更高（P = 0.003）。Y2 中的血液代谢物（使用 d0 值作为协变量）在各处理组之间相似（P > 0.10），除了在第 7 天血浆尿素氮浓度降低（P = 0.025）和第 28 天 NEFA 浓度增加（P = 0.050）。这些研究表明，在接收日粮中使用 SBH 可以支持与 DRC 相似的体重增加。
