This study aimed to determine dietary effects of energy and protein levels on slaughter performance, carcass yield and qualities of selected sheep breeds. Fifty yearling lambs with a mean IBW of 19.31±1.7 kg (Mean ± SD) were randomly distributed into five dietary treatments i.e., mEmP(minimum Energy and Protein), MEMP (medium energy and protein), MEHP(medium Energy and high Protein), HEMP(high energy and medium protein), and HEHP(high Energy and high Protein) diets in randomized complete block design with 2*5 factorial arrangements. The minimum, medium, and high energy diets were: 2.388, 2.866, and 3.344 Mcal/kgDM with the corresponding 10, 16, and 20% CP diets. The diets were formulated in a total mixed ration from wheat bran, maize grain, peanut cake, and pasture hay feed ingredients. Then, all lambs were slaughtered using standard commercial procedures. Hararghe sheep had higher (p< 0.001) slaughter and carcass measurements (SBW, EBW, HCW, CCW), Commercial and Real dressing percentage, total edible portion, and back fat thickness by 2.7, 1.75, 1.61 and 1.42 kg, 1.44 and 2.27%, 3.55% and 1.47 mm respectively than Afar sheep. The highest records of carcass parameters were observed for lambs fed with the MEHP diet. The MEMP diet was optimum diet producing leaner carcasses with optimum fat acceptable both for domestic and export markets.

Keywords: carcass measurement, dressing percentage, slaughter measurement