Genetic and phenotypic analysis of meat quality traits in lamb and correlations to carcass composition

Abstract

Meat quality traits in lamb were examined and their genetic parameters and genetic correlations to carcass composition were estimated. Dissection was performed on 350 lamb carcasses and the weight of lean, fat and bone recorded for each animal, as well as the weight of m. longissimus dorsi (LD) and m. semimembranosus (SM). The temperature and pH of the LD and SM were recorded at 1, 4, 7, 10, 13 and 48h post-slaughter. Intramuscular fat (IMF), protein and moisture, Minolta meat colour (redness, a*; yellowness, b*; and lightness, L*) and Ez-drip loss of the LD were recorded. Heritability estimates ranged from 0.17 to 0.69, which was significant for all traits except for SM, a*, b* and ultimate pH of the LD. Genetic correlations with lightness (L*) were high and negative for a* and high and positive for b*. IMF was moderate to highly genetically correlated to the weight and percentage of carcass fat (almost significant), and negatively correlated to the percentage of lean and SM (p<0.05). The pH decline was not significantly different between the LD and SM, although a higher temperature was found for the SM at 4, 7 and 10h post-slaughter. Ultimate pH of the LD and SM recorded 48h post-slaughter were 5.63 and 5.65, respectively. Ez-drip loss was minimal. The cost of recording many of the traits analysed limited the size of the dataset. Hence, the genetic parameters presented for several traits analysed were estimated with relatively large standard errors and should be confirmed with a larger dataset.