Comparative evaluation of growth performance, carcass yield and meat quality attributes of crossbred Dorper and Awassi, and indigenous Menz sheep supplemented with brewery spent grain

Abstract

This study evaluated growth performance, carcass characteristics, and meat quality of pure Menz sheep, and 50% Dorper × Menz (D×M) and 50% Awassi × Menz (A×M) crosses under two feeding regimes: brewery spent grain plus concentrate (F1) or concentrate-only (F2) used as supplement with natural pasture hay as basal diet. The supplemental feeds were isonitrogenous and isocaloric. Forty-eight castrated yearling rams (16 per genotype) were assigned to the dietary treatments in a 2 × 3 factorial design and the experiment lasted for a period of 90 days. Data on nutrient intake, body weight changes, carcass measurements, and sensory scores were taken and analyzed using the standard procedures. Breed significantly (p < 0.05) influenced final body weight, average daily gain, and carcass traits, with DxM and AxM outperforming Menz sheep. F2 yielded greater feed conversion efficiency than F1 (p < 0.05), while digestibility coefficients did not differ among the treatments (p > 0.05). DxM sheep had higher cold carcass weight, loin cut weight, and fat thickness (p < 0.01), and dressing percentage was greater in F2. Sensory evaluation showed that meat from Menz sheep was preferred from tenderness, juiciness, flavor, and overall acceptability (p < 0.01) compared to other sheep breeds. Significant breed × feed interactions for sensory attributes indicated genotype-specific dietary response. Strong positive correlations (r = 0.72–0.95, p < 0.01) between growth and carcass yield highlight the predictive value of performance traits for meat output. Based on marginal rate of return and superior carcass yield, A×M sheep are strongly recommended under both brewery spent grain plus concentrate (F1) and concentrate-only (F2) feeding regimes, while D×M sheep are recommended under the F1 feeding regime.