There is uncertainty whether feed efficiency traits are related to energetic efficiency. The objective of this study was to utilize comparative slaughter data to evaluate the relationships of feed efficiency traits with maintenance energy requirements (MEm) and efficiency of metabolizable energy (ME) use for maintenance (km) and gain (kg). Published data were compiled (31 studies, 214 treatment means) on metabolizable energy intake (MEI) and composition of empty body gain in growing cattle. Data analyses were performed using R statistical software considering each treatment mean as an independent experimental unit. Assuming fasting heat production (FHP) varies only due to empty body protein (EBP) composition, it was computed as 295 kcal/kg EBP.75. MEm, km, and kg were computed from the nonlinear relationship between heat production and MEI. Residual intake (lower is more efficient) was computed as the residual from linear regression of MEI on EBW and EBW gain (RMEI) or MEI on EBP, retained energy as protein and retained energy as fat (RMEIc). Residual gain (higher is more efficient) was computed as the residual from linear regression of EBW gain on EBW and MEI (REBG) or retained energy on EBP and MEI (RRE). MEI was positively correlated with RMEI (0.46) and RMEIc (0.44), and EBW gain was correlated with REBG (0.58) and RRE (0.39). FHP was correlated with RMEIc (-0.25). MEm was weakly correlated with RMEI (0.19), RMEIc (0.22), and REBG (-0.26), but strongly correlated with RRE (-0.51). km was moderately correlated with RMEI (-0.35), but strongly correlated with REBG (0.49), RMEIc (-0.59), and RRE (0.79). kg was strongly correlated with RMEI (-0.69), REBG (0.47), RMEIc (-0.89), and RRE (0.70). Correlations among feed efficiency traits were strong (>±0.48). In conclusion, feed efficiency traits using retained energy as the dependent variable had stronger correlations with maintenance energy requirements than those using feed intake as the dependent variable.

中文翻译：

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PSIV-2 利用生长和育肥牛的比较屠宰研究评估饲料效率性状与能量代谢之间的关系

饲料效率性状是否与能量效率相关尚不确定。本研究的目的是利用比较屠宰数据来评估饲料效率性状与维持能量需求 (MEm) 和代谢能量 (ME) 用于维持 (km) 和增益 (kg) 的效率之间的关系。已发表的数据汇编了（31 项研究，214 种治疗方法）关于可代谢能量摄入 (MEI) 和生长牛的空腹增重组成。使用 R 统计软件进行数据分析，将每个处理平均值视为独立的实验单元。假设空腹产热 (FHP) 仅因空体蛋白 (EBP) 组成而变化，则计算为 295 kcal/kg EBP.75。MEm、km 和 kg 是根据产热和 MEI 之间的非线性关系计算得出的。剩余摄入量（越低效率越高）计算为 MEI 对 EBW 和 EBW 增益 (RMEI) 或 MEI 对 EBP 的线性回归的残差，作为蛋白质的保留能量和作为脂肪的保留能量 (RMEIc)。剩余增益（越高越有效）计算为 EBW 增益对 EBW 和 MEI (REBG) 的线性回归的残差或 EBP 和 MEI (RRE) 上的保留能量。MEI 与 RMEI (0.46) 和 RMEc (0.44) 呈正相关，EBW 增益与 REBG (0.58) 和 RRE (0.39) 相关。FHP 与 RMEic (-0.25) 相关。MEm 与 RMEI (0.19)、RMEIc (0.22) 和 REBG (-0.26) 弱相关，但与 RRE (-0.51) 强相关。km 与 RMEI (-0.35) 中度相关，但与 REBG (0.49)、RMEIc (-0.59) 和 RRE (0.79) 密切相关。kg 与 RMEI (-0.69)、REBG (0.47)、RMEIc (-0.89)、和 RRE (0.70)。饲料效率性状之间的相关性很强（＞±0.48）。总之，与使用采食量作为因变量的饲料效率性状相比，使用保留能量作为因变量的饲料效率性状与维持能量需求的相关性更强。