Performance Recording and Genomics

If you can’t measure it, you can’t manage it!

This has been conditioned into me throughout my professional life so it was natural for me to want to be able to tangibly measure my flocks improvement over time.  As a result of continued focus over a number of years I am now proud to be able to say that the Kimbolton Flock is in the Top 1% of UK recorded Texel flocks – now the work starts to stay there!

So why should YOU care about that?

Well in simple terms a flock’s physical performance directly affects its profitability, so if earning more money is important to you please read on…

Increased profitability is achieved by using efficient, modern animals that require less inputs (mainly feed) but who have increased output (e.g. produce more kg of meat as quickly as possible), and this is what drives the improved financial returns to your business.

The most cost effective way to lift flock productivity permanently is through selective breeding using elite genetics. In other words, the careful choice of animals known to have the right genetics to produce the type of lambs you and your customers are looking for – ones that grow fast and have the right carcass conformation.

So what data is collected and what happens to it?

In simple terms a range of data is collected at key points in an animals life (birth, 56 days, then around 40kg, then if female when it is tupped as a yearling). This is then input and analysed by a model called BLUP (Best Linear Unbiased Predictor). The output provides an estimate of the genetic component of the animals performance in the form of Estimated Breeding Values (EBV’s) and these can be used to make informed breeding decisions. 

These EBVs predict the superiority, or inferiority of breeding stock for specific traits that include:

Eight Week Weight (kg)
Mature Size (kg)
Litter Size (lambs) (%)
Maternal Ability (kg)
Twenty One Week Weight
Muscle Depth (mm)
Fat Depth (mm)
CT Lean Weight (kg)
CT Fat Weight (kg)
CT Gigot Muscularity (mm)

Newer measurements are being collected for additional traits like;

Lambing Ease (%)
Birth Weight (kg)
Worm Resistance

Accuracy Values

All of the data provided has an accuracy value provided too – PLEASE ENSURE YOU TAKE NOTICE OF THIS!

Accuracy Values indicate the likelihood of an EBV changing (up or down) as more information on the animal becomes available.  Accuracy values account for the risk involved in making breeding decisions and provide buyers with the confidence that an EBV is accurate.

For any trait, the accuracy of the EBV is influenced by several factors:-

  • Amount of information for the animal (lambs will therefore have lower accuracy due to not having any progeny yet)
  • Amount of information from relatives
  • Heritability of the trait
  • Amount of information from traits correlated with the trait of interest and the strength of these correlations
  • Number of animals being compared (contemporaries)

At 95% accuracy scan weight can be expected to be within 3kg (+/- 1.5kg) of EBV prediction
At 60% accuracy scan weight can be expected to be within 8kg (+/- 4kg) of EBV prediction

As you can see the difference between the two is significant therefore always check that the animal you are buying has (at a minimum) been ultrasound scanned, if not be suspicious and ask why the breeder is selling on figures but not recording the traits.

In 2023, the Texel Society introduced a simplified way to analyse this array of hard to interpret information by building a financial model so moving forwards every animal has a £ value and everyone understands money!

Two indexes are available depending on if you want to produce slaughter lambs (Terminal Index) or breed replacements (Replacement Index).  The higher the value the better the animal – simple!


Genomic technology will become increasingly available to UK sheep breeders and this  could lead to a revolution in the number of traits that are selected for and the speed at which selection can occur.

Genomic tools are particularly useful for selecting for traits which are hard to measure. For example, disease resistance, ewe longevity, meat quality traits and even the selection of animals with lower greenhouse gas emissions.

A DNA test should not, however, be seen as a replacement for recording the performance of individual animals. Ironically, phenotypic records – that is to say records of animals’ physical performance and appearance – will become even more important in the genomic age.

In practice this means that individual records will still be needed, but the inclusion of genomic technology will mean increased accuracy and, for some traits, not all animals will need to be recorded so more breeders and commercial lamb producers will be able to access these improvements.

In the meantime continuing participation in performance recording will be vital for those who wish to access developing genomic technologies. With a balanced approach between estimated breeding values, genomic tools, structural soundness and general appearance, the UK sheep industry could see long-term benefits in the genetic merit of the national flock.

You can be sure that the Kimbolton Flock is at the forefront of Genomic  technology developments as the first DNA samples were provided back in 2011 to help better understand the breeds DNA make up. In addition we have been selected as  a Phenotype Farm by the Texel Sheep Society and have participated in Mastitis projects since 2013.

A document containing further information on genomics can be downloaded here Genomics explained


It is important to remember that all of this information is provided to inform and de-risk your buying decision. If you simply purchase based on how it looks on sale day you are taking a big gamble as there are so many things that contribute to how the animal appears (mainly how it has been fed).  Using the combination of EBV’s and your eye (plus a visit to the breeder if you can) is the smart way to ensure you select an animal that will perform and do a good job for you.


Pedigree Performance Recorded Texel Sheep