Carcass characteristics of 5/8 Nellore-3/8 Charolais steers slaughtered at different maturity stages

The carcass quantitative characteristics of 5/8 Nellore-3/8 Charolais steers feedlot finished to reach slaughter weight (SW) of 425. 467 and 510 kg. were studied. At the beginning of the feedlot the average age, weight and body condition were, respectively, 660 days, 361 kg and 2.9 points. The diet offered, with 60:40 roughage: concentrate relation, dry matter basis (DM), contained 10.25% crude protein and 72.18% of total digestible nutrients. The roughage was corn silage with 46.5% of grain in the DM. Cold carcass dressing percentage showed linear relation with SW ( Y = 37.618 +.011Pi (initial weight) +.028SW). However, when dressing percentage was expressed in relation to empty body weight (EB), it was not influenced by SW. Subcutaneous fat thickness expressed per cold carcass ( Y = -15.499 -.001Pi +.047SW), per 100 kg of cold carcass weight (Y = -1.724 -.006Pi +.013SW) and per 100 kg of EB ( Y =-1.124-.003Pi+.008SW) increased as SW increased. Longissimus dorsi area increased linearly with SW ( Y =-33.472+120Pi+.120SW), however, when expressed per 100 kg of cold carcass weight it declined (Y = 45.173 -.023Pi -.028SW), and when expressed per 100 kg of EB, it did not show relationship with SW. The percentage of sawcut declined ( Y = 63.007 -.001Pi -.026SW) while the side cut increased (Y =-3.054 +.005Pi +.030SW), as SW increased. Slaughter weight influenced positively cushion thickness ( Y = 6.223 +.014Pi +.031SW), leg length ( Y = 28.326 +.061Pi +.05SW) and arm perimeter (Y = 9.173+.053Pi +.017SW). Carcass conformation was not alterated by SW.