Genetic Trends for Abattoir Traits

Signet clients measure the performance of the lambs in their flocks (using ultrasound scanning and computed tomography) with the aim of enhancing the value of their commercial progeny when they reach the abattoir.

The challenge in this approach is that it has traditionally focussed on proxy measures (such as scan weight, muscle depth and fat depth) to enhance the traits of real economic interest, namely carcase weight, conformation and days to slaughter.

SRUC geneticists using data collected as part of RamCompare, the National Progeny Test, now have a better understanding of the genetic relationships that exist between those traits measured in the live animals in pedigree flocks and those attributes expressed at the abattoir and in 2025 Signet were able to fit these relationships into Signet’s genetic evaluation to produce more accurate and reliable breeding values for abattoir traits.

What has the evaluation of abattoir data shown?

The latest results derived from this AHDB funded research shows exactly what performance recording has achieved in recent decades.

• Selection for growth rate has reduced days to slaughter in some cases by up to a week. The genetic potential to increase carcase weights at a given age have also increased in most breeds.
• Selection for muscle yield and shape, using both ultrasound scanning and the CT scanner has boosted conformation and carcase weights.
• Carcase fatness has hardly changed, though the breeding values produced are good indicators of fatness within the carcase should producers which to increase or decrease the leanness of carcases.

   

How can ram buyers use this data?

This work clearly shows that when buying Signet recorded rams, commercial ram buyers should select stock sires with high EBVs for Scan Weight and Muscle Depth if they wish lambs to finish quickly and receive a premium for conformation.

In addition to this ram buyers can start using the new breeding values for abattoir traits, such as Days to Slaughter and Carcase Conformation to refine breeding decisions and capitalise on the best genetics the breed has to offer.  

For more information head to the Signet website and use “Sheep Search” and “Flock Finder” to see the breeding values produced for sheep of interest and to find your nearest Signet recorded flock.

Footnote: A note on genetic trends

Genetic trends simply reflect the average performance across a population over time. In Signet’s evaluations there can be big differences between the populations represented in these charts from numerically small breeds, where all of the data is obtained from weight recorded flocks to bigger ones like Suffolk, Charollais and Hampshire Down – where a proportion of the animals (a large proportion in some breeds) are not engaged in weight recording.

Small changes in a large population can still have a big impact at industry level and within a large population there will be flocks making extremely high rates of genetic progress that are perhaps not reflective of the rest of the breed.

When buying a ram from a Signet recorded breeder, ask them to show you their flock genetic trends – which can be produced in just a few seconds from the Signet website.