For all 15 cuts, from the three age groups and 6 fat codes included in theamounted to 91% of total determined protein (N 6.25). Nitrogento-protein conversion factors were calculated for all cuts over age groups and fat classes by dividing total amino acid count (g) with total nitrogen (g). On average, a nitrogen-to-protein conversion factor of 5.74 was found for South African beef (Table 4). The topside cut had the conversion factor (6.18) closest to the Jones factor of 6.25, while the hind shin had the lowest correlation with a conversion factor of 5.22 compared to the Jones factor of 6.25. study, on average, the sum of amino acids per cut