Meat Science Commons^™

A Muscle Hypertrophy Condition In Lamb (Callipyge): Characterization Of Effects On Muscle Growth And Meat Quality Traits, M. Koohmaraie, S. D. Shackelford, T. L. Wheeler, Steven M. Lonergan, M. E. Doumit

Steven M. Lonergan

The present experiment was conducted to determine the effect of the callipyge phenotype on traits affecting muscle growth and meat tenderness. Dorset wethers (n = 40) that were either carriers or non-carriers were fed grain and slaughtered at 169 d of age. Callipyge phenotype did not affect ( P > .05) slaughter weight, hot carcass weight, or weights of the heart, spleen, viscera, kidney-pelvic fat, head, and pelt; however, callipyge lambs had a higher dressing percentage and lighter lungs, liver, and kidneys ( P < .01). Callipyge lambs had reduced fat thickness and marbling score and higher leg scores and longissimus area (34%). Adductor (30%), biceps femoris (42%), gluteus group (31%), longissimus (32%), psoas group (20%), quadriceps femoris (18%), semimembranosus (38%), and semitendinosus (26%) weights were higher in the callipyge phenotype ( P < .01); however, phenotype did not affect ( P > .05) weights of infraspinatus or supraspinatus. Longissimus pH and temperature declines were not affected ( P > .05) …