Carcasses of 122 ram lambs born from Finnsheep X Merino (FM) and Merino (ME) as dam lines, crossed with the Ile de France (IF), SA Mutton Merino (SAMM), Dohne Merino (DM), FM and Merino as sire lines were evaluated for meat production. Significant differences (P < 0,05) were found between sire lines and between dam lines for warm carcass mass, dressing percentage, subcutaneous fat, omentum fat, percentage lean, carcass length and conformation. Sire breeds differed significantly (P < 0,05) from each other in respect of bone, kidney knob channel fat, length of the hind limb, fat thickness at the third lumbar vertebrae, area of tile eye muscle and mass of the liver, while dam lines differed significantly (P < 0,05) for fat score. Lambs born from the Merino sire, had a significantly (P < 0,05) lower dressing percentage, a lower warm carcass mass and more subcutaneous fat than lambs from the other sire lines. Lambs born from the FM dam line had significantly (P < 0,05) less subcutaneous fat and significantly (P < 0,05) more intra-abdominal fat than lambs from the Merino dam line. No significant differences were found between sire lines or between dam lines for total carcass fat, muscular fat or carcass protein. Results suggest that carcass traits differ relatively little between the two dam and also between the five sire lines. The optimum slaughter mass for all genotypes lies at about 40 kg live mass.
Keywords: Crossbreeding, sheep, slaughter and carcass traits