Genetic and phenotypic characterisation of animal, carcass, and meat quality traits from temperate and tropically adapted beef breeds. 3. Meat quality traits

Abstract

Abstract. Abstract. Meat quality measures, including objective measures of tenderness (shear force and compression), were taken on 2 muscles [M. longissimus thoracis et lumborum (LTL) and M. semitendinosus (ST)]from 7566 carcasses from temperate (TEMP) and tropically adapted (TROP) beef cattle breeds. Animals were finished to 1 of 3 market carcass weight end-points (220, 280, or 340 kg) either on pasture or in a feedlot, and in 2 different geographic regions for TROP. Both the phenotypic and genetic expressions of the traits were estimated at each market weight and for each finishing regime. Heritabilities and correlations between the traits were estimated for TEMP and TROP separately. Smaller additive variances and heritabilities were observed for temperate breeds compared with tropically adapted breeds for most of the traits studied. For TROP, the heritability of traits measured on the ST muscle [compression (ST_C), shear force (ST_SF), and L* Minolta lightness value (ST_L*)] was 0.27, 0.42, and 0.16, respectively, and for traits measured on the LTL muscle [compression (LTL_C), shear force (LTL_SF), L* Minolta lightness value (LTL_L*), a* Minolta redness value (LTL_a*), cooking loss % (LTL_CL%), and consumer assessed tenderness score (LTL_TEND)] 0.19, 0.30, 0.18, 0.13, 0.20, and 0.31, respectively. For TEMP, the heritability of traits measured on the ST muscle [ST_C, ST_SF, ST_L*, a* Minolta redness value (ST_a*), cooking loss % (ST_CL%)] was 0.12, 0.11, 0.17, 0.13, and 0.15, respectively, and of traits measured on the LTL muscle (LTL_C, LTL_SF, LTL_L, and LTL_TEND) 0.08, 0.09, 0.17 and 0.18, respectively. Genetic correlations were moderate to high for tenderness measures (shear force and compression) between muscles for the same tenderness measure (e.g. LTL_SF and ST_SF was 0.46 for TROP) and within a muscle for the different measures (e.g. ST_C and ST_SF was 0.83 for TROP). Phenotypic and genetic correlations between LTL_L* and all objective measures of tenderness were negative (e.g. LTL_SF and LTL_L* for TROP was -0.40). The genetic relationship between LTL_SF and LTL_TEND was -0.79 and -0.49 for TROP and TEMP, respectively. Finishing system affected the phenotypic expression of all traits. Pasture-finished, compared with feedlot-finished, animals had higher shear force and compression measures, darker meat colour, and lower sensory tenderness scores for both TEMP and TROP. For TROP, heifers had higher shear force and compression measures, lower sensory tenderness scores, and darker meat colour (lower L* values) than steers. Genetic correlations between markets were generally high and close to unity with the exception of the ST_L*, LTL_L*, ST_C, and ST_SF for TEMP. Geographic region had little effect on the phenotypic and genetic expression of meat quality traits for TROP. Genetic correlations between finishing regimes for all traits were positive and close to unity, with the exception of ST_C and LTL_SF for TEMP, and LTL_L* and LTL_CL% for TROP. Genetic improvement of meat quality traits is a possibility f...

Brahman and Brahman crossbred cattle grown on pasture and in feedlots in subtropical and temperate Australia. 2. Meat quality and palatability

“…Tropically adapted straightbreds (Brahman, Belmont Red, Santa Gertrudis) tended to have lower (more favourable) SFLT than our results. Similar to our findings though, Johnston et al (2003) reported higher CMQ4 results for animals finished in the temperate feedlot. However, there was only a difference of 1.2 units for the tropically adapted straightbreds, whereas crossbreds in our experiment differed by 5.0 units.…”

“…In fact, there was only a difference of 2.4 units in CMQ4 between markets, lending further weight to the conclusion that connective tissue toughness was not a major issue for the meat of these animals. This finding is supported by Johnston et al (2003), who concluded that age-related changes in connective tissue toughness were not large in the Straightbreeding Program in animals up to 42 months of age. In contrast, market · finish interactions showed 12 months difference in age at slaughter for Japanese animals (36 v. 24 months of age) finished on pasture and feedlot, respectively, did result in significant detrimental effects on SFLT, SFST, ICLT and ICST (P < 0.05) and sensory palatability (P < 0.05) in this study.…”

“…In contrast to our findings, Johnston et al (2003) reported heifers had higher SF and IC measures relative to steers. A study by Lawrence et al (2001) found heifers advanced in skeletal and overall maturity at a much faster rate than steers, despite a lack of difference in SF, sensory tenderness or cooking loss between the sexes, supporting our OSSIF results.…”

“…This is consistent with our results for SFLT and ultimate pH, though differences in PHLT and PHST between pasture and grain finishing in our experiment were much smaller. Johnston et al (2003) reported consistent findings in magnitude and direction for SFLT, ICLT, SFST, ICST and CLLT in the Straightbreeding Program for Brahman, Belmont Red and Santa Gertrudis animals finished on pasture and grain in the subtropics. However, their CMQ4 results were lower for straightbred animals (40.9 v. 47.8 for pasture v. feedlot finishing respectively), relative to our results.…”

Genetics of meat quality and carcass traits and the impact of tenderstretching in two tropical beef genotypes

“…The Meat Standards Australia (MSA) grading system predicts meat quality as a tenderness dominated meat quality score (Thompson 2002;Watson et al 2008), via several critical control points identified through extensive consumer taste panel assessment of meat samples from animals of diverse genetic, environmental and nutritional backgrounds. Thompson (2002) and Watson et al (2008), in describing the development and implementation of the MSA system, demonstrated that Bos indicus content had a quantifiable, and negative impact on beef meat quality, which was consistent with the results of studies by Shackelford et al (1995), Pringle et al (1997), Johnston et al (2003b) and Thompson et al (2006). This is particularly relevant to beef production in Australia, where~40% of cattle are B. indicus or B. indicus derived (Bindon and Jones 2001).…”