期刊
ANIMAL PRODUCTION SCIENCE
卷 49, 期 5-6, 页码 383-398出版社
CSIRO PUBLISHING
DOI: 10.1071/EA08275
关键词
feed efficiency; genetic correlations; growth; heritability; tenderness; tenderstretch
资金
- Cooperative Research Centre for Cattle and Beef Quality (and its core partners: The University of New England, NSW DPI, CSIRO, and Queensland DPI)
- Commonwealth
- Meat and Livestock Australia
- Australian Centre for International Agricultural Research
- Northern Pastoral Group
Meat quality and carcass traits were measured for 2180 feedlot finished Brahman (BRAH) and Tropical Composite (TCOMP) steers to investigate genetic and non-genetic influences on shear force, and other meat quality traits. Genetic and phenotypic correlations were estimated between carcass and meat quality traits, and with live animal measurements collected in steers from weaning to feedlot exit, and their heifer half-sibs up to their first mating, which were managed in Australia's tropical or subtropical environments. Left sides of carcasses were tenderstretched (hung by the aitch-bone) while right sides were conventionally hung (by the Achilles tendon). Tenderstretching reduced mean shear force by 1.04 kg, and phenotypic variance by 77% of that observed in conventionally hung sides. Genotype differences existed for carcass traits, with TCOMP carcasses significantly heavier, fatter, with greater eye muscle area, and lower retail beef yield than BRAH. TCOMP had lower shear force, and higher percent intramuscular fat. Meat quality and carcass traits were moderately heritable, with estimates for shear force and compression of 0.33 and 0.19 for BRAH and 0.32 and 0.20 for TCOMP respectively. In both genotypes, estimates of heritability for carcass traits (carcass weight, P8 and rib fat depths, eye muscle area and retail beef yield) were consistently moderate to high (0.21 to 0.56). Shear force and compression were genetically correlated with percent intramuscular fat (r(g) = -0.26 and -0.57, respectively), and meat colour (r(g) = -0.41 and -0.68, respectively). For TCOMP, lower shear force was genetically related to decreased carcass P8 fat depth (r(g) = 0.51). For BRAH steers and heifers measured at pasture, fatness traits and growth rates were genetically correlated with shear force, although the magnitude of these relationships varied with time of measurement. Net feed intake was significantly genetically correlated with carcass rib fat depth (r(g) = 0.49), eye muscle area (r(g) = -0.42) and retail beef yield (r(g) = -0.61). These results demonstrate that selection to improve production and carcass traits can impact meat quality traits in tropically adapted cattle, and that genotype specific evaluations will be necessary to accommodate different genetic relationships between meat quality, carcass and live animal traits.
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