Effect of the genetic merit for backfat thickness on the meat quality of steers

The objective of the present study was to evaluate the effects of the genetic merit for backfat thickness (GMB) and subcutaneous fat thickness (FT) on meat quality traits of Nellore and crossbred (½ Aberdeen Angus + ½ Nellore) steers. The animals were obtained by mating Nellore cows with Nellore or Aberdeen Angus bulls. Both paternal genetic groups were selected to provide positive (+, high GMB) or negative (-, low GMB) expected progeny differences (EPDs) in terms of backfat thickness. Two hundred and fourteen animals were obtained, reared on a pasture, and finished either in feedlot or semi-confinement systems. The steers were slaughtered, and the backfat visual scores, FT, marbling visual scores and meat color aspects were evaluated for the carcasses (24 h postmortem). In non-aged and aged meat samples (for 14 days), the pH, color, drip loss, cooking loss, and shear force were analyzed. The moisture content and intramuscular fat concentrations of the meat were determined. A second experimental approach was proposed to assess the influence of the FT class (low = 3.66 ± 0.58 mm; medium = 4.99 ± 0.49 mm and high = 6.81 ± 1.06 mm) on the same variables as in the original study. The GMB influenced (P < 0.05) the FT and carcass fattening but did not influence (P > 0.05) the physicochemical traits or the fat content of the meat. Steers with a low, medium, or high FT provided meats with similar physicochemical attributes. Thus, GMB increases subcutaneous fat deposition without affecting meat quality traits.