| Abstrakt: |
Live, carcass composition and carcass quality characters were measured on 646 progeny of Polled Hereford sires and Angus × Holstein dams and used to calculate heritability estimates and phenotypic and genetic correlations. The heritability estimates for 205-day weight (.35) and live body dimensions (−.01 to .19) were similar to previous reports, with the estimates for slaughter weight per day, .36, and carcass weight per day, .21, slightly lower than previous studies. Heritability estimates for fat thickness, trimmed round percent, trimmed loin percent, longissimusarea, cutability and edible portion per day of age were .41, .26, .10, .42, .44 and .20, respectively. Heritability estimates for marbling, WB shear, and taste panel tenderness, juiciness and flavor were .33, .17, .23, .26, and −.06, respectively. The highest heritability estimate for any body dimension was .19 for body width. These results indicate that sire effects on most economic live and carcass traits are of similar importance in progeny of high-milk-producing beef-dairy crossbred cows compared to those from pure bred beef cows.Growth and traits reflecting carcass meatiness were positively correlated phenotypically, but some of the genetic relationships were negative. Genetic correlations of growth and meatiness traits with carcass quality traits indicated some undesirable genetic antagonism, but the correlations were not consistent and generally low. At the individual slaughter weight endpoints used in this study (415 and 467 kg for heifers and steers, respectively), heifers were at a more advanced stage of maturity. None of the sex × sire interactions were significant, indicating that these two effects were additive. |
