Graduate Student Research Poster Competition

Thirty selected sides (from 30 whole carcasses) received high voltage (500 V, 60 Hz, 90s: HV) electrical stimulation (ES) within 45 min postmortem and the opposite sides served as controls (NES). Twelve unsplit whole carcasses received low voltage (50 V, 60 Hz, 15s: LV) ES within 3 min after stunning. Following stimulation, each side received one of three temperature conditioning treatments: (A) 30" C for 3 h followed by chilling at 2" C; (B) chilling at 2" C until longissimus muscle (LM) reached 20" C, followed by 3 h at 30" C; (C) chilling at 2" C (REG). Both HV-ES and LV-ES (Pc.05) improved lean maturity scores as compared to controls. With LV-ES both lean maturity and overall maturity scores were improved by both the 30" C and 20" C treatments compared to REG. The LM temperature for the 30" C treatment was higher at 2 h (P<.05) and 4 h (Pc.01) while the LM temperature for the 20" C treatment was higher at 12 to 24 h as compared to 30" C and REG. Both HV-ES and LVES significantly lowered the pH values at 2 h through 12 h as compared to controls and reduced the time required for the ATP level to reach the minimum value. Both ES treatments significantly changed the R values (A248/A260, A2501A260 and A258/A250) at 2 h and 4 h. The ES treatments also significantly influenced firmness, fragmentation and connective tissue (CT) residue as measured by sensory panel and significantly reduced lnstron shear values of loin steaks. No significant differences were found for ATP or R values as influenced by conditioning treatments. These results indicate that both HV-ES and LV-ES improved lean maturity, influenced ATP and R values, improved tenderness of loin steaks and can be influenced by temperature conditioning treatments. Collagen Stability and Hormone Status of Growing Rams and Wethers