Corn is the most common grain ingredient fed to feedlot cattle in the U.S. and most corn goes through some processing to increase the energy availability. This study examined the effects of a novel corn processing method on the growth performance, starch digestibility, and blood metabolites of growing steers compared with traditional corn processing methods. Angus-cross steers [n = 218; body weight (BW) = 230 ± 18.5 kg] were sorted into pens of 6 or 7 steers upon arrival and fed a common receiving diet for 2 d prior to being weighed, processed, and starting dietary treatments (n = 12 pens/treatment) on d 0. Treatments included diets with dry rolled corn (ROLL), steam flaked corn (FLAKE), and high shear dry extruded corn (EXT; High-Gel Insta-Pro International, Grimes, IA). Corn was included at 30% DM of a corn silage and SweetBran-based diet. Due to illness concerns, diets were adjusted to reduce corn in the diet to 25% on d 5; in feed antibiotic was fed d 5 to 9, and all calves were weighed and administered Draxxin (1.1 mL/45.45 kg) on d 17. Final BW were collected on d 37 and 38 and serum (glucose, insulin) and fecal samples (total tract starch digestibility) were collected from one steer per pen. Data were analyzed using the Mixed procedure of SAS 9.4 (Cary, NC) with pen as the experimental unit. Treatment did not affect midpoint (d 17) BW or average daily gain (ADG) from d 0 to 17 (P ≥ 0.31). Final BW, ADG, and dry matter intake were not different between treatments (P ≥ 0.15). Feed efficiency (gain:feed) was greatest in EXT (0.261) compared with ROLL (0.232) with FLAKE (0.259) being intermediate and not different from other treatments (P = 0.007). Total tract starch digestibility was determined using the equations from Zinn et al. (2007) and was increased in EXT and FLAKE compared with ROLL (P = 0.0002). Serum glucose and insulin on d 36 were not affected by treatment (P ≥ 0.19). Overall, a growing diet of 25% high shear dry extruded corn increased feed efficiency and total tract starch digestibility over dry rolled corn and resulted in similar performance to steers fed steam flaked corn.

中文翻译：

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250 玉米加工对肉牛生长性能、淀粉消化率和血液代谢物的影响


玉米是美国饲养场牛最常见的谷物原料，大多数玉米都经过一些加工以增加能源可用性。本研究检查了与传统玉米加工方法相比，一种新的玉米加工方法对生长犊牛生长性能、淀粉消化率和血液代谢物的影响。安格斯杂交公牛 [n = 218;体重 （BW） = 230 ± 18.5 公斤] 在到达时被分选到 6 或 7 头公牛的围栏中，并在称重、加工和开始饮食治疗 （n = 12 笔/治疗） 之前喂食 2 天在第 0 天。处理包括干玉米片 （ROLL）、蒸汽玉米片 （FLAKE） 和高剪切干挤压玉米 （EXT;High-Gel Insta-Pro International，爱荷华州格莱姆斯）。玉米的 30% DM 是玉米青贮饲料和基于 SweetBran 的日粮。由于对疾病的担忧，调整饮食以将第 5 天饮食中的玉米含量降低到 25%;在饲料中，第 5 至 9 天饲喂抗生素，第 17 天称重并给予 Draxxin （1.1 mL/45.45 kg）。在第 37 天和第 38 天收集最终 BW，并从每栏一头公牛收集血清 （葡萄糖、胰岛素） 和粪便样本 （总道淀粉消化率）。使用 SAS 9.4 （Cary， NC） 的混合程序以笔为实验单位分析数据。治疗不影响第 0 天至第 17 天的中点 （d 17） 体重或平均日增重 （ADG） （P ≥ 0.31）。最终 BW 、 ADG 和干物质摄入量在处理之间没有差异 （P ≥ 0.15）。与 ROLL （0.232） 相比，EXT （0.261） 的饲料效率 （增益：饲料） 最高，FLAKE （0.259） 处于中等水平，与其他处理没有差异 （P = 0.007）。使用 Zinn 等人的方程确定总淀粉消化率。 （2007） 并且与 ROLL 相比，EXT 和 FLAKE 增加 （P = 0.0002）。第 36 天血糖和胰岛素不受治疗影响 （P ≥ 0.19）。总体而言，与干轧玉米相比，25% 高剪切干挤压玉米的生长饲料提高了饲料效率和总淀粉消化率，并导致与饲喂蒸汽玉米片的公牛相似的性能。