2011 Annual Report 1a.Objectives (from AD-416) In a range sheep production environment, evaluate different biological types of sheep for reproductive efficiency, rate and efficiency of growth, carcass composition, meat quality, and mature size. Use quantitative genetic methods to identify physical and physiological criteria for enhancing reproductive efficiency and other economically important traits, including meat quality, quantity, and flavor. 1b.Approach (from AD-416) Reproductive efficiency, rate and efficiency of growth, carcass composition, meat quality, and mature size will be evaluated for different biological types of sheep in a range sheep production environment. New genetic information gained from these evaluations on traits affecting production efficiency, and the relationship of the traits to growth and carcass characteristics, will be used to develop new composite terminal sire lines. These sire lines will be used with appropriate maternal lines to meet target market specifications for commercial lambs and produce more desirable end products that meet consumer demands, without sacrificing reproductive efficiency. Documents SCA with Virginia Poly Inst. & State U. 3.Progress Report ARS Research Scientists at the U.S. Sheep Experiment Station in Dubois, ID and their collaborator at Virginia Tech University have analyzed a portion of the data collected during a 3-year study to characterize Columbia-, USMARC Composite-, Suffolk-, and Texel-sired F1 lambs for traits of survival, growth, feed efficiency, carcass composition, and meat quality. In 2011, three manuscripts were written, coauthors reviewed the manuscripts, and first authors are currently making revisions. The three manuscripts will be submitted to peer-reviewed scientific journals in FY 2011. A fourth manuscript is currently in preparation. The genetic information gained from this study has been used to initiate the development of a new composite (i.e., in this case, genetics from three breeds of sheep) terminal-sire genetic line of sheep. The initial breed crosses, with the planned proportion of each of the three founding breeds, were realized in 2010, and, as of 2011, approximately 300 of the sheep have been produced and are under evaluation. Project is monitored by in-person collaboration, and continued correspondence by phone, and email.