The objectives of rearing cattle for beef include producing as much meat as possible of the highest possible quality, sustainably (which includes profitably).

Improving carcase quality

Beef carcase quality in GB is assessed by the EUROP system, which is an indirect indicator of meat yield from the carcase. Tables 1 and 2 show that there has been some improvement in the carcase quality of beef cattle over the ten years to 2014, with carcases generally becoming leaner and of better conformation. This may reflect better selection for slaughter. Nevertheless in 2014 only 55% of prime cattle slaughtered in Britain met the target of E, U or R for conformation and 1, 2, 3 or 4L for fat class.

One means of improving carcase quality is to breed cattle for better carcase characteristics, improving the genetic attributes for carcase traits. Currently this is being done indirectly through measuring growth rate and associated carcase traits on the live pedigree animal – fat depth and muscle depth/area using ultrasound. We know the value of this to be £4.9 million per annum (Amer et al., 2015). It may be possible, however to breed directly for the traits measured in the abattoir.

Abattoir data for genetic evaluation

When combined with other national databases, abattoir data are suitable for producing national beef genetic evaluations for the traits farmers are paid for. This project being undertaken by Scotland’s Rural College (SRUC) is a follow on from an AHDB funded feasibility study which showed the data could be collected, validated and merged. The focus of the project is on producing genetic parameters and genetic evaluations for carcase weight, conformation and fat class for those breeds with sufficient data in the BCMS database. Unfortunately some breeds do not have sufficient data because they are numerically small or the sire has not been recorded on the passport for enough animals.

The project, funded by AHDB (Beef & Lamb and Dairy) and Hybu Cig Cymru (Meat Promotion Wales) is now nearing completion. Nearly 4 million carcase records have been assembled and matched with BCMS records and other data sources to assemble the best possible ‘superpedigree’ file.

From this set of data a smaller set was extracted for the calculation of genetic parameters (heritability values and genetic correlations). The analysis so far has resulted in the development of genetic parameters for carcase traits (fat class, weight (in relation to age) and conformation). Heritabilities (within breed) are mainly in the range of 0.2 to 0.4 which is very encouraging – indicating the breeding for these traits using commercial carcase data is not only possible, but also likely to result in good rates of progress.

A larger subset of the data has been used to produce EBVs for 2,416,966 animals (those with a 3 generation pedigree) for the carcase traits. Table 3 shows a summary of these EBVs for the UK population. These EBVs have been rebased to 2010 born animals so an average of 0 is not expected, and EBVs can be interpreted as a comparison to the average 2010 born animals, i.e. a carcase weight EBV of 2kg has the genetics to produce 2kg more than the average 2010 born animal.

The most extreme animals were checked for each EBV to confirm the result. In most cases these were animals for which slaughter data were available and they showed an extreme, but valid phenotype. Given they had directly measured data, these animals also tend to have generally high accuracies and even if restricted to those that have 10 progeny we still see a wide range in EBVs reported. This variation also means that good rates of genetic progress are likely.

Simple correlations were also undertaken between the raw phenotypes and the resulting EBV. Generally, correlations suggest a strong relationship between observed phenotype and the underlying genetics but this relationship was weakest for slaughter age, suggesting a strong effect of management/ environment which is unsurprising. The relationship was strongest for conformation, suggesting a very strong genetic component, again unsurprising.

The project team are now preparing to examine the EBVs for a sample of animals by breed and discuss the use of the new carcase trait EBVs with the breed societies.

Improving eating quality

A wide range of factors can influence the eating quality of beef available to consumers. Delivering optimum quality relies on the adoption of a whole chain approach. Individual retailers, however, adopt differing specifications to suit their business needs and the practices intended to improve meat quality, operated in isolation, may not be fully effective. In 2011, AHDB Beef & Lamb (EBLEX) conducted a retail beef survey following concerns that there was an undesirable and avoidable degree of variation in the toughness of English beef at retail. Sirloin steaks and topsides from six major retailers were shear force tested for tenderness over a three month period and the findings reported.

This was repeated in 2015, although the sample was expanded to include the increasingly prominent discount retailers. This has enabled assessment of changes in the tenderness of beef at retail. The results from sirloin steaks suggest an improvement in quality. This is thought to be partly due to changes in packaging methods, from high oxygen modified atmosphere packs to vacuum packs and vacuum skin packs.

Animal age and meat quality

Despite improved attention to processing and packaging practices to improve eating quality, there remains uncertainty about the attention being given to live-animal factors. In particular there has been relaxation of rules regarding the maximum age of cattle sourced for quality beef specifications. The correct age limit for quality beef production from steers and heifers is often debated. With some prime beef cattle not being ready for slaughter until 30–36 months of age there is a need to know if meat from these older cattle is tougher. A project, being undertaken at SRUC (funded by AHDB), has been established to examine the effects of alternative lifetime growth paths on animal performance, carcase characteristics and meat eating quality parameters.

The first phase of the project was to assemble Limousin cross finishing cattle at the SRUC Beef Research Centre. These cattle have been finished according to three target growth paths:
• Short duration growth path: 12–16 months of age
• Medium duration growth path: 18–26 months of age
• Long duration growth path: 28–36 months of age
Both steers and heifers were allocated to alternative growth path groups taking individual sire into account so that no one sire dominated within any one group for either steers or heifers.

All 24 animals from the short-term finishing growth path group completed their finishing phase and were slaughtered in 3 batches in the summer of 2013. All 24 animals from the medium term finishing growth path group were slaughtered in 3 batches in autumn 2013 – spring 2014. The long term group were slaughtered in the 2015/16 winter. This long-duration group had a pattern of growth typical on many commercial systems with periods of growth interrupted by periods of little or no growth.

Once slaughtered, bone-in loin joints of beef were recovered from all carcases and dispatched to the University of Bristol for subsequent assessment and eating quality analysis. This includes assessment of the composition, including thickness and weight of gristle and intramuscular fat content, and finally trained sensory panel assessment of eating quality. These analyses are not yet complete, but the results of the gristle weight indicate that whilst the weight of gristle increased with each growth phase, in the short and medium periods, the gristle as a proportion of both the joint and the loin weight did not differ. However, in those animals that had been subject to a growth check, and hence longer growth period, the gristle had increased disproportionally to the joint growth.

The results of this work will help inform guidance to supply chains on the appropriate age of cattle at slaughter to ensure quality prime beef production.

Conclusion

While improvements have been made in both the carcase and eating quality of beef in England, further research underway will help deliver further improvements to ensure that the customer receives the quality they require.

Reference

Amer, P., Byrne, T., Fennessy, P., Jenkins, G., Martin-Collado, D. and Berry, D. (2015). Review of the genetic improvement of beef cattle and sheep in the UK with special reference to the potential for genomics. AbacusBio Limited.