摘要
Four trials were conducted to evaluate the effects of flint corn processing and the replacement of corn with citrus pulp (CiP) in diets for Nellore feedlot cattle. In a 103-d finishing trial, 216 Nellore bulls (350 ± 24 kg initial BW) were used in a randomized complete block design with a 2 × 4 factorial arrangement of treatments. Factors included 2 processing methods, either ground corn (GC) or steam-flaked corn (FC), with CiP replacing each corn type at 4 levels (0, 25, 50, and 75% of DM). All diets contained 12% sugarcane bagasse and 88% concentrate (DM basis). Treatments were also evaluated in metabolism trials, in which 10 ruminally cannulated Nellore steers (389 ± 37 kg) were assigned to 2 independent but simultaneous 5 × 5 Latin squares, each using 1 method of corn processing (GC and FC). Interactions (P < 0.05) between corn processing and CiP inclusion level were observed for final BW, DMI, ADG, G:F, and HCW. With FC-based diets, added CiP linearly decreased final BW (P = 0.04), whereas with GC-based diets, added CiP quadratically increased final BW (P = 0.002). With FC-based diets, the inclusion of CiP linearly increased DMI (P = 0.03) and linearly decreased ADG (P = 0.03) and G:F (P = 0.001). Increasing CiP in GC-based diets quadratically increased DMI (P = 0.001), ADG (P = 0.005), and HCW (P = 0.003). In FC-based diets, CiP inclusion had no effect on HCW (P = 0.21). Dressing percent, LM area, and 12th-rib fat were not affected by diet (P ≥ 0.05). For steers fed GC diets, CiP inclusion in the diet quadratically decreased the molar proportion of isovalerate (P = 0.001) but linearly increased ruminal butyrate (P = 0.006). No differences (P ≥ 0.16) were observed for total VFA concentrations, acetate:propionate ratio, and ruminal NH3–N as CiP replaced GC. For steers fed FC diets, the molar proportion of acetate linearly increased (P = 0.002) whereas the proportion of propionate was linearly decreased (P < 0.001), resulting in a linear increase (P = 0.001) in the acetate:propionate ratio. Replacing corn with CiP linearly reduced NEm (P = 0.001) and NEg (P < 0.001) of FC-based diets but did not affect (P = 0.15) NE values of CG-based diets. Steam flaking flint corn improved cattle performance in this trial more than has been reported for dent corn in the published literature.
摘要译文
进行了四项试验以评估燧石玉米加工的效果以及用Nellore饲养场牛的日粮中的柑橘果肉（CiP）替代玉米。在103天的整理试验中，216名内洛尔公牛（350±24公斤初始体重）用于随机完整的方块设计，采用2×4因子排列的治疗。因素包括2种处理方法，（GC）或蒸汽压片玉米（FC），CiP以4种水平替代每种玉米类型（DM的0,25,50和75％）。所有日粮含有12％甘蔗渣和88％浓缩物（DM基准）。还在代谢试验中评估了治疗，其中10只带瘤肛管的Nellore阉牛（389±37kg）被分配到2个独立但同时的5×5拉丁方，每种都使用1种玉米加工方法（GC和FC）。在最终BW，DMI，ADG，G：F和HCW中观察到玉米加工和CiP包含水平之间的相互作用（P 0.05）。使用基于FC的饮食时，添加CiP使最终体重线性降低（P \x3d 0.04），而在基于GC的饮食中，添加的CiP使得最终体重（P \x3d 0.002）二次增加。使用基于FC的饮食时，包括CiP线性增加DMI（P \x3d 0.03）和线性减少ADG（P \x3d 0.03）和G：F（P \x3d 0.001）。在基于GC的饮食中增加CiP以DMI（P \x3d 0.001），ADG（P \x3d 0。005）和HCW（P \x3d 0.003）。在基于FC的饮食中，CiP包含对HCW没有影响（P \x3d 0.21）。敷料百分比，LM面积和第12肋骨脂肪不受饮食影响（P≥0.05）。对于喂食GC饮食的阉牛，饮食中CiP的添加使得异戊酸的摩尔比例（P \x3d 0.001）减少，但瘤胃丁酸的线性增加（P \x3d 0.006）。无差异（P≥0。16）观察到总VFA浓度，乙酸盐：丙酸盐比率和瘤胃NH 3 -N，其中CiP代替GC。对于饲喂FC饮食的阉牛，乙酸盐的摩尔比例线性增加（P \x3d 0。002），而丙酸盐的比例呈线性下降（P 0.001），导致醋酸盐：丙酸盐比例呈线性增加（P \x3d 0.001）。用CiP替代玉米线性降低基于FC的日粮的NEm（P \x3d 0.001）和NEg（P 0.001），但不影响（P \x3d 0.15）基于CG的日粮的NE值。在该试验中，蒸汽压片火石玉米改善了牛的表现，这在已发表的文献中报道的更多。
V. N. Gouvêa;F. Batistel;J. Souza;L. J. Chagas;C. Sitta;P. R. B. Campanili;D. B. Galvani;A. V. Pires;F. N. Owens;F. A. P. Santos. Flint corn grain processing and citrus pulp level in finishing diets for feedlot cattle[J]. Journal of Animal Science, 2016,94(2): 665–677