Meat Quality and Disposition of F2 Nellore x Angus Cross Cattle

Abstract

Correlations between cattle disposition and meat quality were expected to be found, as well as differences in meat quality traits among contemporary groups, sires, and families nested within sires. Temperament effects on meat quality were evaluated in Nellore × Angus F2 cross cattle (n = 238) over a 3-yr period, with harvests twice a year. Five aspects of temperament -- aggressiveness, nervousness, flightiness, gregariousness, and overall temperament -- were evaluated at weaning and yearling ages, as well as an overall temperament score at slaughter. USDA quality grade, fat thickness, adjusted fat thickness, hot carcass weight, USDA yield grade, and chemical fat were correlated negatively (P < 0.05) with weaning temperament scores, aggressiveness, nervousness, flightiness, gregariousness, and overall temperament. No significant correlation was found between Warner-Bratzler shear and weaning temperament traits. USDA quality grade and live weight were correlated negatively (P < 0.05) with yearling temperament scores, nervousness, flightiness, gregariousness, overall temperament score as well as the temperament score observed at slaughter. Fat thickness and adjusted fat thickness also were correlated negatively (P < 0.05) with yearling gregariousness, yearling overall, and slaughter overall temperament. Yearling gregariousness was correlated positively (P < 0.05) with Warner-Bratzler shear from both ES and NON carcasses. Least squares mean differences were evaluated among contemporary groups, sires, and families nested within sires for overall temperament traits and meat quality traits. Contemporary group differences found were thought to be explained by environmental factors, as seen in contemporary group 5, which had the smallest ribeye possibly caused by the shortest feeding period. Steers sired by 297J had the lowest (calmest) temperament scores, most 12th rib fat, highest numerical yield grade, and the heaviest weights. Sire 437J had steers with the highest (wildest) temperament scores, the least fat and lowest numerical yield grade. This population was designed to identify QTL for economically important traits and appears to be useful for this purpose because of the differences found both between and within families.