EFFICIENT PRODUCTION OF HIGH QUALITY BEEF IS CRITICAL TO SUSTAINABILITY OF THE INDUSTRY. LONG-TERM COMPETITIVENESS AND FUTURE SUSTAINABILITY OF THIS INDUSTRY DEPEND ON CONTINUED HIGH BEEF DEMAND BY CONSUMERS. ADVANCES IN ANIMAL AND PLANT GENETICS, ANIMAL HUSBANDRY PRACTICES, AND GROWTH PROMOTING TECHNOLOGIES SUCH AS &BETA;-ADRENERGIC AGONISTS (BA) HAVE INCREASED THE EFFICIENCY OF BEEF PRODUCTION, WHILE DECREASING RELIANCE ON NATURAL RESOURCES, YET WE DO NOT UNDERSTAND HOW THEY INFLUENCE CONSUMER ACCEPTABILITY OF MEAT. IT HAS RECENTLY BECOME APPARENT THAT GROWTH PROMOTING TECHNOLOGIES AND SUPRANUTRITIONAL ZINC SUPPLEMENTATION PROVIDE ECONOMICAL MEANS TO IMPROVE CATTLE GROWTH RATES. THESE TECHNOLOGIES MAY, IN PART, ACT BY INFLUENCING THE SKELETAL MUSCLE PHOSPHOPROTEOME. UNFORTUNATELY, THESE OBSERVATIONS HAVE BEEN MADE INDEPENDENTLY WITH RESPECT TO ANIMAL GROWTH OR PRODUCT QUALITY, AND NOT AS A UNIFIED STUDY. THIS PROJECT ADDRESSES A CRITICAL KNOWLEDGE GAP REGARDING THE LINKAGE BETWEEN MUSCLE GROWTH AND PRODUCT QUALITY. THIS PROJECT WILL EVALUATE STEER GROWTH IN RESPONSE TO ZINC AND BA SUPPLEMENTATION AND WILL DETERMINE HOW STEER GROWTH RATE AND ZINC NUTRITION AFFECT THE PROTEINS (PROTEOME AND SPECIFICALLY THE PHOSPHOPROTEOME) OF BOTH LIVING AND POSTMORTEM SKELETAL MUSCLE.SPECIAL EMPHASIS WILL BE PLACED ON HOW THESE CONTRIBUTE TO VARIATIONS IN GROWTH AND MEAT TENDERNESS. IT WILL ADDITIONALLY IDENTIFY NOVEL TARGETS FOR PROTEIN PHOSPHORYLATION THAT MAY INFLUENCE MUSCLE GROWTH AND MEAT TENDERNESS. THIS COLLABORATIVE PROJECT PROVIDES AN IDEAL, INDUSTRY RELEVANT MODEL TO EXAMINE THE ROLE OF THE PHOSPHOPROTEOME IN MODULATING MUSCLE GROWTH AND MEAT QUALITY. IN SUMMARY, THIS PROPOSAL ADDRESSES THE EFFECT OF GROWTH RATE AND ZINC NUTRITION ON MOLECULAR AND WHOLE ANIMAL ASPECTS OF BEEF PRODUCTION AND PRODUCT QUALITY.THIS PROJECT WILL ADDRESS KEY QUESTIONS RELATED TO IMPROVING THE SUSTAINABLITLY OF THE BEEF INDUSTRY AND WILL IMMEDIATLY IMPACT SCIENTISTS, BEEF NUTRITON AND PRODUCTION SPECIALISTS.