Genetic groups and levels of fat thickness on the quality of meat from bulls

Abstract

This study was carried out to evaluate the effect of genetic groups and carcass fat thickness levels on unfreeze losses (UFL), cooking losses (COL), pH, shear force (SF), frequency and diameters of slow-twitch-oxidative and red color (SO), fast-twitch-glicolytic and intermediate color and fast-twitch-glycolitic and white color (FG) on Longissimus muscle of bulls finished in feedlot. It were evaluated NEL – Nellore; LIN - ½ Limousin + ½ Nellore and RAN - ½ Angus + ½ Nellore genetic groups slaughtered with fat thickness levels of 3 or 5 mm. There was an interaction between genetic group RAN and fat thickness levels to the characteristics of UFL, COL, pH, SF and redness. The NEL produced meat darker than the crossbred, and had higher ultimate pH. However, the meat of these animals had lower UFL, COL and SF when compared to crossbred. Bulls RAN had the highest frequency of fast oxidative glicolytic fiber and lowest in slow-twitch oxidative fibers, and larger diameters for these fibers. Difference in meat quality among genetic groups are found in the smallest fat thickness levels of the carcass, while these differences cease to exist when the slaughter occurs with higher fat thickness levels. Fat thickness levels did not affect on meat quality of bulls finished in feedlot.