Breed effects, retained heterosis, and estimates of genetic and phenotypic parameters for carcass and meat traits of beef cattle

Abstract

Retained heterosis for meat traits was estimated in F3 generation castrate males in three composite populations of beef cattle finished on two levels of dietary energy density (2.82 Mcal of ME and 3.07 Mcal of ME and 11.50% CP) and serially slaughtered at four end points at intervals of 20 to 22 d. Breed effects were evaluated in nine parental breeds (Red Poll [R], Hereford [H], Angus [A], Limousin [L], Braunvieh [B], Pinzgauer [P], Gelbvieh [G], Simmental [S], and Charolais [C]) that contributed to the three composite populations (MARC I = 1/4 B, 1/4 C, 1/4 L, 1/8 H, 1/8 A; MARC II = 1/4 G, 1/4 S, 1/4 H, 1/4 A; and MARC III = 1/4 R, 1/4 P, 1/4 H, and 1/4 A). Breed effects were important (P < .01) for all carcass and meat traits evaluated. Dietary energy density and slaughter group affected (P < .05) most traits evaluated. The effects of retained heterosis were not consistent among composites. For the mean of the three composites, retained heterosis was significant only for percentage of 9-10-11th rib fat and for percentage of retail product. Phenotypic correlations indicated that marbling score was a poor predictor of palatability attributes of individual carcasses. Estimates of heritability were intermediate to high for measures of fatness but were generally low for palatability attributes. The high negative genetic correlation (-.56) between percentage of retail product and marbling score and the relatively low genetic correlations between percentage of retail product and palatability attributes suggests the need for simultaneous attention to percentage of retail product and palatability attributes rather than to marbling score. Correlations among breed group means were generally high for measures of fatness with palatability attributes and were high and negative for percentage of retail product with marbling score and with other measures of fatness. Limited opportunity exists for selecting among breeds to achieve high levels of marbling in the longissimus muscle simultaneously with a high percentage of retail product. These results suggest that the most logical approach to resolution of the genetic antagonism between favorable carcass composition and less favorable palatability attributes is to form composite breeds with breed contributions organized to achieve an optimum balance between favorable carcass composition and desirable palatability attributes at optimum slaughter weights.

Quantitative and molecular genetic influences on properties of beef: a review

“…Results from those studies suggest that heterosis for Warner Bratzler shear force values ranges from moderately favourable to slightly unfavourable (about -10 to 5%, Winer et al 1981;Peacock et al 1982;Anderson et al 1986;Marshall et al 1987;Gregory et al 1994aGregory et al , 1994b, although some Bos indicus × Bos taurus crosses may have higher levels of favourable heterosis (DeRouen et al 1992). There were no observed effects of heterosis on sensory evaluation of juiciness, tenderness and flavour (Winer et al 1981;Gregory et al 1994b) or for cooked meat colour and overall acceptability (Winer et al 1981).…”

“…Estimates of genetic correlations between marbling (or intramuscular fat percentage) and Warner Bratzler shear force values of the striploin (M. longissimus dorsi) include an average of -0.25 from 2 studies (Marshall 1994); -1.00 ± 0.45 in crossbred populations (Gregory et al 1994b); -0.57 ± 0.16 (Shackelford et al 1994a); -1.00 ± 0.48 in crossbred populations (Gregory et al 1995); estimates ranging from -0.16 ± 0.58 to -1.09 ± 0.58, depending on length of post mortem aging (Wulf et al 1996); -0.55 ± 0.22 (Wheeler et al 1996); estimates ranging from -0.12 ± 0.45 to +0.63 ± 0.53, depending on length of post mortem aging (O'Connor et al 1997); and estimates ranging from -0.06 to -0.24, depending on the breed grouping (Elzo et al 1998). In general, phenotypic correlations were closer to zero than genetic correlations in most studies.…”

“…A moderate to strong genetic antagonism exists between carcass fatness traits and retail beef yield percentage. Estimates of genetic correlations between retail beef yield percentage and marbling scores or intramuscular fat percentages include a weighted mean correlation of -0.25 (Koots et al 1994b); -0.57 ± 0.15 (Shackelford et al 1994a); -0.56 ± 0.19 (Gregory et al 1994b); and -0.60 ± 0.20 (Gregory et al 1995).…”

“…Estimates based on the striploin (M. longissimus dorsi) include an average estimate from 2 studies of -0.16 (Marshall 1994); 0.22 ± 0.26 (Gregory et al 1994b); and 0 ± 0.28 (Gregory et al 1995).…”

“…Application of processing techniques such as electrical stimulation, tenderstretching and correct aging of meat can be used to overcome the effects of cold shortening (Harris and Shorthose 1988). It is therefore possible that beef tenderness measured either with or without correct application of processing techniques to overcome cold Barkhouse et al (1996); Crews and Franke (1998); Gregory et al (1994b); Gregory et al (1995); Hirooka et al (1996); Johnston et al (1992a); O'Connor et al (1997); Shackelford et al(1994a); Splan et al (1998);Van Vleck et al (1992); Wheeler et al (1996); Wulf et al (1996). B Individual estimates of heritability were weighted by the relative amount of information (inverse of their estimated sampling variance).…”