Genetic associations between daily gain and live fleshiness of station-tested young bulls and carcass and meat quality traits of commercial intact males in Piemontese cattle.

The aim of this study was to investigate genetic relationships between beef traits of station-tested young bulls and carcass and meat quality traits (MQ) of commercial intact males in Piemontese cattle. Phenotypes for daily gain (DG) and live fleshiness traits (width at withers: WW; shoulder muscularity: SM; loin width: LW; loin thickness: LT; thigh muscularity: TM; thigh profile: TP) and thinness of the shin bone (BT) were available for 3,109 and 2,183 performance-tested young bulls, respectively. Carcass daily gain (CDG), carcass conformation (SEUS), pH at 24 h (pH24h) and 8 d after slaughter (pH8d), lightness (L*), redness (a*), yellowness (b*), hue angle (HA), saturation index (SI), drip loss (DL), cooking loss (CL), and shear force (SF) were assessed for 1,208 commercial intact males. (Co) variance components were estimated in a set of twelve 9-traits analyses using REML and linear animal models including all performance-test traits and 1 carcass or MQ trait at a time. Heritabilities \ub1 SE of beef traits ranged from 0.26 \ub1 0.03 (LW) to 0.47 \ub1 0.01 (DG), whereas those of carcass traits and MQ from 0.06 \ub1 0.03 (CL) to 0.63 \ub1 0.04 (HA). The genetic correlation (rg) between DG and CDG was 0.75 \ub1 0.10, indicating that DG, as measured at the test station, is a good indicator of the carcass gain achieved by commercial animals under farms conditions. Daily BW gain of station-tested bulls correlated positively with color traits (from 0.11 \ub1 0.12 to 0.54 \ub1 0.09), ph8d (rg \ub1 SE = 0.31 \ub1 0.11), DL (rg \ub1 SE = 0.29 \ub1 0.17), and CL (rg \ub1 SE = 0.27 \ub1 0.18). Live fleshiness of station-tested bulls exhibited genetic correlations with MQ of commercial animals that were positive for L* and b* (from 0.13 \ub1 0.08 to 0.65 \ub1 0.14) and negative for pH (from \u20130.27 \ub1 0.15 to \u20130.57 \ub1 0.11), CL (from \u20130.16 \ub1 0.23 to \u20130.43 \ub1 0.22), and SF (TM: rg \ub1 SE = \u20130.31 \ub1 0.15; TP: rg \ub1 SE = \u20130.41 \ub1 0.17). The thinness of the shin bone correlated unfavorably with CDG (rg \ub1 SE = \u20130.74 \ub1 0.07) and favorably with SEUS (rg \ub1 SE = 0.65 \ub1 0.17), CL (rg \ub1 SE = \u20130.39 \ub1 0.13), and SF (rg \ub1 SE = \u20130.32 \ub1 0.17). The estimated genetic correlations indicate that selection to increase DG, as measured at the test station, exerts moderate adverse effects on MQ. Because selection emphasis is greater for live fleshiness than for DG, the correlated response in MQ and carcass traits is expected to be influenced to a greater extent by selection for muscularity, even though these traits are less heritable than DG