Callipyge (CLPG, n=16) and normal (N, n=11) lambs were produced from Polypay dams and Dorset sires heterozygous for the CLPG gene to study the effects of the gene on growth and carcass and meat quality parameters. CLPG lambs had higher average daily gain than N lambs (0.26 vs 0.23 kg/day, p<.05); however, the CLPG gene did not affect feed efficiency. Lambs were slaughtered in three groups to achieve moderate uniformity in slaughter weight. At the time of slaughter, weights of head, pelt, and internal organs were recorded. Two leg muscles, two shoulder muscles, the longissimus dorsi muscle, and two loin chops cut 2.5 cm thick, were dissected from each carcass. CLPG lambs had a higher dressing percent (p<.01) and lighter head, pelt, liver (all p<.01), and kidney/pelvic fat (p<.05). CLPG lambs had less fat over 12th rib (p<.05) and larger ribeye area (p<.01). CLPG lambs had greater weights of Biceps femoris (42%, p<.05), Semimembranosus (34%, p<.01), Triceps brachii (20%, p<.05), longissimus dorsi muscle (29%, p<.01) and whole leg (6%, p<.05) than N lambs. All the dissected muscles from all carcasses and one whole leg from each ewe lamb carcasses (n=11) were cooked to an internal temperature of 70��C. CLPG carcasses produced higher Warner-Bratzler shear values for loin chops (4.79 vs 2.93 kg, p<.01), Biceps femoris (3.94 vs 2.92 kg, p<.05), Semimembranosus (4.75 vs 3.46 kg, p<.05) and Longissimus dorsi muscle (5.29 vs 3.4 kg, p<.01) than N lambs. However, no significant differences were detected in shear values for Biceps femoris (3.10 vs 3.04 kg) or Semimembranosus (3.77 vs 3.29 kg) when the muscles were dissected after roasting the whole leg. The CLPG gene also had no effect on the shear values for two dissected shoulder muscles (Deltoid and Triceps brachii). The two genotypes did not differ in either cooking loss or percent moisture in any of the muscles compared. / Graduation date: 1998