摘要
Comparing heat production after ad libitum (ADLIB) and restricted (RESTRICT) feeding periods may offer insight into how residual feed intake (RFI) groups change their energy requirements based on previous feeding levels. In this study, the authors sought to explain the efficiency changes of high- and low-RFI steers after feed restriction. To determine RFI classification, 56 Angus-cross steers with initial body weight (BW) of 350 ± 28.7 kg were individually housed, offered ad libitum access to a total mixed ration, and daily intakes were recorded for 56 d. RFI was defined as the residual of the regression of dry matter intake on mid-test BW0.75 and average daily gain. High- and low-RFI groups were defined as >0.5 SD above or below the mean of zero, respectively. Fourteen steers from each high and low groups (n = 28) were selected for the subsequent 56-d RESTRICT period. During the RESTRICT period, intake was restricted to 75% of previous ad libitum intake on a BW0.75 basis, and all other conditions remained constant. After the RESTRICT period, both RFI groups had decreased maintenance energy requirements. However, the low-RFI group decreased maintenance energy requirements by 32% on a BW0.75 basis, more (P
摘要译文
比较任意采食（ADLIB）和限制采食（RESTRICT）后的产热量，可以洞悉残余采食量（RFI）组如何根据以前的采食量改变能量需求。在这项研究中，作者试图解释饲料限制后高和低RFI FI牛皮的效率变化。为了确定RFI等级，分别安置了56头初始体重（BW）为350±28.7千克的安格斯跨ste牛皮，随意获得总混合日粮，并记录了每天的摄入量56 d。 RFI定义为测试中期BW 0.75 和平均日增重时干物质摄入量回归的残差。高-和低-RFI组分别被定义为高于或低于零平均值的> 0.5 SD。在接下来的56 d RESTRICT期间，分别从高和低组（n = 28）中选择了14个ste牛。在限制期间，以BW 0.75 为基础，采食量限制为以前随意采食量的75％，其他所有条件保持不变。限制期之后，两个RFI组均降低了维护能源需求。但是，低RFI组在BW 0.75 的基础上将维护能量需求降低了32％，更多（P
Emily M Andreini [1]; Sheyenne M Augenstein [1]; Carrie S Fales [1]; Roberto D Sainz [1]; James W Oltjen [1]. Effects of feeding level on efficiency of high- and low-residual feed intake beef steers[J]. Journal of Animal Science, 2020,98(10)