Effect of genotype and age on some carcass and meat quality traits of beef carcasses subjected to the South African classification system

• The SA classification system gives limited description of carcass and meat quality.
• Carcass and meat quality were evaluated from different genotypes within the same carcass class.
• Conformation and bruise score were similar among genotypes, while subcutaneous fat score varied.
• Meat quality varied among animals of the same age across genotypes than within genotype.
• Genotype classification can provide an accurate technique of classifying beef carcasses.

Genotype and age effects on pH24, L*, a*, b*, tenderness (WBSF), cooking (CL %), and thawing loss (TL %) of beef carcasses subjected to the South African classification system were determined. Carcass traits (bruising, subcutaneous fat (SF), and conformation) were also measured. Meat quality measurements were taken on the longissimus thoracis et lumborum (n = 175) of A, AB, B, and C carcasses from Angus, Bonsmara, Fleckvieh, Non-descript, and Simmental genotypes. No bruises were evident in all carcasses. All carcasses scored medium conformation (class 3) while in SF classification, class 2 had the greatest frequency (66.3%). Genotypic effects (P < 0.05) were observed for a*, hue angle (HA), pH24, TL%, CL%, and WBSF between steers with six, seven, and eight incisors. Notable differences (P < 0.05) were observed for tenderness where Angus and Simmental had least tender meat while Non-descript and Fleckvieh had the tenderest meat within the C-age class. Meat quality varied within animals of the same age-class across genotypes.