Fig. 2
Effect of exogenous adrenocorticotropic (ACTH) administration (1.98 IU/kg metabolic BW0.75) on plasma cortisol concentration (ng/mL) in beef heifers differing in phenotypic residual feed intake (RFI). The values are expressed as Lsmeans with SEM. RFI, P = 0.45; Time, P < 0.001; RFI × Time interaction, P = 0.06. SEM: High RFI = 0.712; Low RFI = 0.688