2011 Annual Report 1a.Objectives (from AD-416) Elucidate adaptive mechanisms that promote energy efficiency in the range beef cow. Various measurements exposing physiological/metabolic changes will be evaluated based on their genetic origins. 1b.Approach (from AD-416) Cows and their daughter have been developed and managed based upon a factorial approach to prenatal and post natal nutritional management. Production, physiological and metabolic measurements will be used to assess cow longevity (based on reproductive rate) and economic efficiency. Microarray analysis will be implemented to establish the association between genetic background and important traits related to stress adaption. 3.Progress Report Methodology development for microarray evaluation is progressing. This has included identifying programming language for advanced statistical analysis. Phenotypic data evaluation has been completed. Progress is monitored by ADODR through personal communication (face to face, email and telephonically), in addition to communications at scientific meetings.