The objective of this study was to determine the effects that increasing doses of encapsulated butyric acid and zinc (BZ) have on feedlot steer growth performance, rumen morphometrics and small intestine histology (data not statistically analyzed), dietary net energy utilization, and carcass characteristics. Steers [n = 272; shrunk body weight (BW) = 360 kg ± 74 kg] were assigned to dietary treatments [0 (CON), 1, 2, or 3 g BZ/kg diet dry matter] in a randomized complete block design (RCBD) with pen (n = 32 total; n = 8 per treatment) as experimental unit. Pens were blocked by cattle source and location within the feedyard. Cattle were fed until visually assessed to have 1.27 cm rib-fat and were shipped for harvest at a commercial beef abattoir. Carcass and liver health data were recorded. A subset of steers (n = 8 total; n = 2 per treatment) was harvested at the SDSU Meat Laboratory to collect empty body measurements, rumen samples for morphometric analysis, and duodenal and ileal samples for histological analysis to provide context to feeding trial outcomes. Feedlot growth performance data was calculated on a carcass-adjusted basis: hot carcass weight (HCW)/0.625. Data were analyzed as a RCBD with fixed effects of BZ inclusion level and block was considered a random effect; pre-planned contrasts for CON vs. BZ, plus linear, and quadratic responses were tested. No differences (P ≥ 0.11) were observed for final BW, dry matter intake, average daily gain (ADG), feed conversion efficiency (G:F), performance calculated dietary net energy, HCW, ribeye area, rib-fat thickness, marbling score, estimated empty body fat, or distribution of USDA yield grade (YG) 1, 3, 4, 5, and USDA quality grade among treatments. A tendency (P = 0.10) was observed for CON vs. BZ for calculated YG. Tendencies were detected for USDA YG 2 carcass distribution (linear; P = 0.07) and for normal and abscessed liver prevalence (quadratic; P = 0.08). Dressed yield tended to be greater (P = 0.08) for BZ vs. CON and increased with dose (linear; P = 0.05). Receiving period shrunk BW, ADG, and G:F were improved (P ≤ 0.02) for BZ supplemented steers compared to CON. Data from this study suggests that the addition of BZ to feedlot finishing diets for improving receiving period growth performance and decreasing the prevalence of abscessed livers should be further investigated

中文翻译：

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胶囊化丁酸和锌对肉牛饲养场阉牛生长性能、日粮净能量利用率、瘤胃形态、小肠组织学和胴体特性的剂量影响


本研究的目的是确定增加胶囊化丁酸和锌 (BZ) 剂量对育肥场公牛生长性能、瘤胃形态和小肠组织学（数据未进行统计分析）、日粮净能量利用率和胴体特性的影响。转向 [n = 272；缩小的体重（BW）= 360 kg ± 74 kg]被分配到饮食治疗[0（CON）、1、2或3 g BZ/kg饮食干物质]，采用随机完全区组设计（RCBD），用笔（总共 n = 32；每个处理 n = 8）作为实验单位。猪圈因牛源和饲养场内的位置而被堵塞。饲养牛直至肉眼评估其肋骨脂肪为 1.27 厘米，然后运至商业牛肉屠宰场进行收获。记录屠体和肝脏健康数据。在 SDSU 肉类实验室收获了一部分阉牛（总共 n = 8 头；每次处理 n = 2 头），收集空体测量数据、用于形态测定分析的瘤胃样本以及用于组织学分析的十二指肠和回肠样本，为喂养试验结果提供背景信息。饲养场生长性能数据是根据胴体调整后计算的：热胴体重量 (HCW)/0.625。数据被分析为具有 BZ 包含水平固定效应的 RCBD，而块被认为是随机效应；测试了 CON 与 BZ 的预先计划对比，以及线性和二次响应。最终体重、干物质摄入量、平均日增重 (ADG)、饲料转化效率 (G:F)、性能计算日粮净能、HCW、肋眼面积、肋骨脂肪厚度、大理石花纹没有观察到差异 (P ≥ 0.11)评分、估计的空体脂肪或 USDA 产量等级 (YG) 1、3、4、5 和 USDA 质量等级在处理间的分布。观察到 CON 与 CON 的趋势（P = 0.10）。 BZ 为计算出的 YG。检测了 USDA YG 2 屠体分布（线性；P = 0.07）以及正常和脓肿肝脏患病率（二次；P = 0.08）的趋势。与 CON 相比，BZ 的修整产量往往更高 (P = 0.08)，并且随着剂量的增加而增加（线性；P = 0.05）。与 CON 相比，补充 BZ 的公牛的受种期体重、平均日增重和毛重均有所改善 (P ≤ 0.02)。这项研究的数据表明，应进一步研究在饲养场肥育日粮中添加 BZ 以改善受精期生长性能并降低肝脏脓肿发生率