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The objective of this study was to identify blood metabolites associated with variation primarily in residual feed intake (RFI) in two populations of beef steers at the University of Guelph and University of Alberta, Canada, representing the discovery and validation populations, respectively. Other productivity performance traits including average body weight (ABW), average feed intake (AFI), dry matter intake (DMI) and average daily gain (ADG) were also investigated. In the discovery population, blood plasma samples were obtained from 32 steers (16 high- and 16 low-RFI, from a population of 112 steers and maximizing the divergence between groups for RFI) at three periods 1, 2 and 3, corresponding to weeks 2, 6 and 10 respectively of the 140. d feeding and performance test. In the validation population, blood samples were obtained from 20 (10 high and 10 low RFI) steers from periods 1 and 2 corresponding to weeks 2 and 6 of a 90. d feeding test period. Metabolite concentrations in plasma were determined using nuclear magnetic resonance (NMR) and multiple regression analysis was performed in SAS 9.1. Creatine and glycine were associated (P |
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