Department of Animal Science, Iowa State University, Ames, IA.
J Anim Sci. 2018 Apr 3;96(3):1159-1170. doi: 10.1093/jas/skx063.
To determine the effects of trace mineral (TM) supplementation and hormone implant strategy on growth and carcass characteristics of cattle, 72 Angus-cross steers (388 ± 17 kg) were blocked by body weight (six steers per pen) to a 2 × 3 factorial. Factors included growth-stimulating implant (GS): day 0 with Component TE-IS, reimplanted day 56 with Component TE-200 (IMP) or no implant (NoIMP), and TM supplementation (TM): no supplemental TM (CON), TM supplemented at national (NASEM, 2016). Nutrient requirements of beef cattle. 8th ed. Washington, DC: The National Academics Press) recommendations of 10 Cu, 30 Zn, 20 Mn, 0.10 Se, 0.15 Co, and 0.50 I (mg/kg; REC), or TM supplemented at feedlot consultant recommendations of 20 Cu, 100 Zn, 50 Mn, 0.30 Se, 0.20 Co, and 0.50 I (mg/kg; IND). Steers received a finishing diet for 124 d in GrowSafe bunks and were harvested on day 125. Data were analyzed in SAS as a 2 × 3 factorial with steer as the experimental unit (n = 12 per combination). Day -7 liver trace mineral concentrations were used as a covariate in analysis. There were no GS × TM effects for liver Zn, Mn, Se, or Co (P ≥ 0.11) on day 70 or 125. Implanted steers had lesser liver Cu and Mn on day 70 (P ≤ 0.05) and day 125 compared with NoIMP. There was a GS × TM interaction for liver Cu on day 125 (P = 0.05) where IMP/REC, IMP/IND, and NoIMP/REC had greater liver Cu than NoIMP/CON, which had greater liver Cu than IMP/CON. There was a TM effect for liver Cu on day 70 (P < 0.01) with IND having greater liver Cu than REC and CON. There was a TM effect (P ≤ 0.01) for liver Mn and Se on day 70 where IND had greater Mn and Se than CON, with REC being intermediate. There was a TM effect (P < 0.01) on liver Mn on day 125 where IND had greater liver Mn than CON and greater (P < 0.01) liver Se than CON and REC on day 125, whereas day 125 liver Se was greater in REC vs. CON. Implanted steers had greater (P < 0.01) dry matter intake (DMI), final body weight (BW), overall average daily gain (ADG), G:F, and hot carcass weight (HCW) than NoIMP. Overall DMI was affected by TM (P < 0.01) with REC and IND being greater than CON. There was a TM effect for carcass-adjusted final BW, ADG, and DMI (P ≥ 0.03) and a tendency for TM to affect adjusted G:F (P = 0.07). There was a TM effect (P = 0.03) for HCW where IND was greater than CON and REC. There was a GS × TM (P = 0.02) for ribeye area (REA); within IMP, CON were greater than IND, whereas REC were intermediate while NoIMP had smaller REA, regardless of TM supplementation. Additional research is needed to better determine trace mineral requirements of finishing beef steers for optimal performance.
为了确定痕量矿物质 (TM) 补充剂和激素植入策略对牛的生长和胴体特性的影响，将 72 头安格斯杂交公牛（388±17kg）按体重分组（每栏 6 头），进行 2×3 析因试验。因素包括生长刺激植入 (GS)：第 0 天用 Component TE-IS 进行处理，第 56 天用 Component TE-200 (IMP) 或无植入 (NoIMP) 进行重植入，以及 TM 补充剂 (TM)：无补充 TM (CON)、按国家 (NASEM，2016) 推荐量补充 TM（10Cu、30Zn、20Mn、0.10Se、0.15Co 和 0.50I，mg/kg；REC）或按牧场顾问推荐量补充 TM（20Cu、100Zn、50Mn、0.30Se、0.20Co 和 0.50I，mg/kg；IND）。牛在 GrowSafe 牛床中接受育肥日粮 124d，于第 125 天进行屠宰。数据在 SAS 中以牛为实验单位（每组组合 12 个）进行 2×3 析因分析。在分析中，第-7 天的肝脏痕量矿物质浓度用作协变量。GS×TM 对第 70 天或 125 天肝脏 Zn、Mn、Se 或 Co 无影响（P≥0.11）。植入的牛在第 70 天（P≤0.05）和第 125 天的肝脏 Cu 和 Mn 较少，与 NoIMP 相比。在第 125 天，GS×TM 对肝脏 Cu 有交互作用（P=0.05），其中 IMP/REC、IMP/IND 和 NoIMP/REC 的肝脏 Cu 大于 NoIMP/CON，而 NoIMP/CON 的肝脏 Cu 大于 IMP/CON。第 70 天，TM 对肝脏 Cu 有影响（P＜0.01），IND 的肝脏 Cu 大于 REC 和 CON。第 70 天，TM 对肝脏 Mn 和 Se 有影响（P≤0.01），IND 的肝脏 Mn 和 Se 大于 CON，而 REC 则介于两者之间。第 125 天，TM 对肝脏 Mn 有影响（P＜0.01），IND 的肝脏 Mn 大于 CON，肝脏 Se 大于 CON 和 REC（P＜0.01），而 REC 的肝脏 Se 大于 CON。植入的牛比 NoIMP 的干物质采食量（DMI）、最终体重（BW）、总平均日增重（ADG）、G:F 和热胴体重（HCW）更高（P＜0.01）。总体 DMI 受 TM 影响（P＜0.01），REC 和 IND 大于 CON。TM 对胴体调整后的最终 BW、ADG 和 DMI 有影响（P≥0.03），TM 对调整后的 G:F 有影响趋势（P=0.07）。TM 对 HCW 有影响（P=0.03），其中 IND 大于 CON 和 REC。GS×TM 对肋眼面积（REA）有影响（P=0.02）；在 IMP 内，CON 大于 IND，而 REC 则介于两者之间，而 NoIMP 的 REA 较小，无论 TM 补充与否。需要进一步研究，以更好地确定育肥牛的痕量矿物质需求，以达到最佳性能。
