9 May 2011

2 minute read

The low heritabilities estimated for meat quality traits, such as juiciness and tenderness, and the obvious difficulty involved in measuring these phenotypes, limits the effectiveness of traditional quantitative breeding. And making progress with these traits using direct measurement is likely to be time-consuming and costly.

So says Dr Gill, from Edinburgh Roslin Institute. “For these reasons, we believe that the next step in the improvement of such traits is to investigate whether associations exist between meat quality traits and genetic loci, possibly starting from candidate genes.

“If significant associations can be found, then marker-assisted selection could be implemented. And this process has the added advantage of being able to assign breeding values to live animals, so that post-slaughter scoring is not necessary.”

Sensory traits are known to be important to the consumer and will influence their consumption of meat, specifically beef. But these traits are difficult to measure and often require the use of taste panels to assess the complex parameters involved in the eating experience.

Such panels are potentially a large source of measurement error, which may reduce the effectiveness of breeding programmes based on the data they generate. So the aim of Dr Gill’s study was to assess the quality of such taste panel-derived sensory traits as well as calculating genetic parameters and residual correlations for these traits along with a further set of traditional carcass quality traits.

The study examined a sample of 443 Aberdeen Angus-cross animals collected from 14 breeder–finisher farms throughout Scotland. To assess the quality of the taste panel measurements, three consistency statistics were calculated: panel-member consistency, or the extent to which an individual panel member varied in their scoring for a given trait over the period of the experiment; repeatability, or the consistency with which an individual panel member was able to score a trait on repeated samples from the same animal; and reproducibility, or the extent to which taste panel members agreed with each other when scoring a trait.

“These consistency statistics were moderately high, particularly for panel-member consistency and reproducibility, with values ranging from 0.48 to 0.81 and 0.43 to 0.73 respectively,” said Dr Gill. “Estimated heritabilities were low for most of the sensory taste-panel-evaluated traits where the maximum value was 0.16 for overall liking. Residual correlations were high between many of the closely related sensory traits, although few significant correlations were found between the carcass quality data and meat quality traits.”