Aryloxy propanolamines for improving livestock production

Disclosed is a compound represented by structural formula (I); R1 is a substituted or unsubstituted aryl group. R2 and R3 are independently -H, a C1-C4 straight chained or branched alkyl group. R4 and R5 are independently -H, a C1-C4 straight chained or branched alkyl group or, taken together with the nitrogen atom to which each is bonded, a non-aromatic heterocyclic ring. Ring A and Ring B are independently further substituted with zero, one or two substituents. Physiologically acceptable salts of structural formula shown above are also included. Also disclosed is a method promoting growth, efficiency of feed utilization and/or production of lean body mass in a livestock animal. The method comprises administering to the animal an effective amount of one or more compounds represented by the structural formula as shown or a physiologically acceptable salt thereof.