Effects of the percentage of Texel or Rouge de l'Ouest genes in lambs on carcass characteristics and meat quality

This study investigated the effects of the percentage of Texel or Rouge de l'Ouest (Rouge) genes in lambs (0, 50, 75 or 100%; the remainder being Greyface (Border Leicester X Scottish Blackface)) on lamb carcass characteristics and meat quality. Ewe lambs were slaughtered at 34, 40, 46 and 52 kg and ram lambs were slaughtered at 40, 46, 52 and 58 kg live weight. Dressing proportion increased (P < 0.001) by 0.53 and 0.27 g carcass weight per kg live weight for each 1% increase in Texel or Rouge genes respectively. Carcass conformation classification increased (P < 0.001) by 0.016 and 0.007 units (on a five-point scale) for each 1% increase in Texel or Rouge genes respectively. Carcass fat depth measures were reduced by Texel and Rouge genes such that at a constant fat depth end point, carcass weight could be increased by 0.029 and 0.023 kg for each 1% increase in Texel or Rouge genes. Carcass lean content increased (P < 0.001) by 0.99 and 0.27 g/kg for each 1% increase in Texel or Rouge genes. Subcutaneous fat content was reduced (P < 0.001) by 0.36 and 0.29 g/kg for each 1% increase in Texel or Rouge genes. Intermuscular fat content was reduced (P < 0.01) by 0.38 g/kg per 1% increase in Texel genes, whereas Rouge genes had no effect. Similarly, bone content was reduced (P < 0.01) by Texel genes only (0.31 g/kg per 1% increase in Texel genes). Warner-Bratzler shear force values showed a quadratic effect with increasing Texel and Rouge genes, with an initial decrease from 0 to 50% followed by an increase to 100%. Cooking loss increased (P = 0.05) as the percentage of Rouge genes in lambs increased. Increasing the percentage of Texel or Rouge genes significantly increased L* values (P < 0.01 and P < 0.05 respectively), b* values (P = 0.05 and P < 0.05 respectively) and H(0) values (P < 0.001).