Abstract This study aimed at estimating the trace minerals net requirements for maintenance and growth of Dorper × Hu ram lambs using the comparative slaughter techniques in 35 lambs of 35–50 kg body weight (BW). Seven lambs were slaughtered at the initial BW (34.93 ± 0.37 kg) to determine the basal whole-body composition. Another seven lambs were fed ad libitum (AL) and then slaughtered when it reached 41.73 ± 0.53 kg BW. The remained 21 lambs were assigned into three treatment groups, seven animals each, and fed 100, 70 or 40% of AL intake, respectively, and were slaughtered when they reached a BW of 49.93 ± 1.03 kg. The net requirements of maintenance were 5.1, 429.3, 94.0 and 48.8 µg/kg empty BW (EBW) for Mn, Fe, Zn and Cu, respectively. The net requirements of growth at 35 kg BW were 0.86, 70.41, 33.46 and 4.31 mg/kg EBW for Mn, Fe, Zn and Cu, respectively. At a BW of 50 kg, the net growth requirements were 0.93, 68.40, 35.20 and 4.15 mg/kg EBW for Mn, Fe, Zn and Cu, respectively. Our data indicated that the Mn and Zn requirements increase, whereas those of Fe and Cu decrease when BW increases. In addition, the net Cu, Mn and Fe requirements for maintenance and Zn, Cu, Mn and Fe requirements for growth of Dorper × Hu hybrid ram lambs were higher than those reported in the NRC but Zn requirements for maintenance matched that of the NRC. Highlights Trace minerals requirements for maintenance and growth vary with sheep genotype or breed. The comparative slaughter method could be a reliable tool for estimating the net requirements of trace minerals in Dorper × Hu ram lambs. Our estimated values for maintenance (Cu, Mn and Fe) and growth (Zn, Cu, Mn and Fe) requirements were higher than those reported in the NRC (2007).

中文翻译：

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测定 35-50 kg Dorper × Hu 杂交公羊羔羊维持和生长所需的微量矿物质

摘要 本研究旨在使用比较屠宰技术对 35 只体重 35-50 公斤 (BW) 的羔羊估计维持和生长杜泊羊羔所需的微量矿物质净需求。七只羔羊在初始体重 (34.93 ± 0.37 kg) 下被屠宰，以确定基础全身成分。另外 7 只羔羊随意喂食 (AL)，然后在达到 41.73 ± 0.53 kg BW 时屠宰。剩下的 21 只羔羊被分配到三个处理组，每组 7 只，分别喂食 100%、70% 或 40% 的 AL 摄入量，并在达到 49.93 ± 1.03 kg 的 BW 时屠宰。Mn、Fe、Zn 和 Cu 的净维护要求分别为 5.1、429.3、94.0 和 48.8 µg/kg 空 BW (EBW)。Mn、Fe、Zn 和 Cu 在 35 kg BW 时的净生长需求为 0.86、70.41、33.46 和 4.31 mg/kg EBW，分别。在 BW 为 50 kg 时，Mn、Fe、Zn 和 Cu 的净生长要求分别为 0.93、68.40、35.20 和 4.15 mg/kg EBW。我们的数据表明，当 BW 增加时，Mn 和 Zn 的需求量增加，而 Fe 和 Cu 的需求量减少。此外，Dorper × Hu 杂交公羊羔羊生长所需的铜、锰和铁净需求量以及生长对锌、铜、锰和铁的需求量高于 NRC 报告的数据，但维持所需的锌与 NRC 相匹配。亮点 维持和生长所需的微量矿物质因绵羊基因型或品种而异。比较屠宰方法可以成为估算杜泊×胡公羊羔羊微量矿物质净需求量的可靠工具。我们对维持（Cu、Mn 和 Fe）和生长（Zn、Cu、