What’s New for 2023?

What’s New for 2023?

We recognise the importance of generating consistency in the monthly breeding values published by Signet.

While the ranking of animals will change as new data is added to the genetic evaluation, breeders generally wish to avoid changes that lead to their animals re-ranking - unless the index of their favourite ram goes up of course!

However, as time moves on the team of geneticists at SRUC do make recommendations on ways to enhance our evaluations and if it is going to help breeders to make better breeding decisions, then we try to take their advice. As a rule, we try and avoid making changes during a recording season, implementing most of these updates in the winter and early spring.

In the coming year breeders should be aware of the implementation of the following enhancements:-

Terminal Sire Evaluation

• A new approach is being used to enhance the assessment of Maternal Ability, Litter Size Born and Litter Size Reared. These changes bring the Terminal Sire Evaluation in line with the updated models used in the Hill and Maternal Evaluations.
• The inclusion of thousands of extra Charollais pedigree records will have a significant impact on the EBVs of some Charollais sheep, enhancing accuracy values and increasing genetic linkage between flocks in the evaluation.

 

Maternal Evaluation

• As for Terminal Sires, a new approach is being used in the assessment of Maternal Ability, Litter Size Born and Reared – but the impact in this analysis is quite small and unlikely to lead to much re-ranking.
• The EBVs for Ewe Mature Weight and Body Condition Score have been enhanced to make better use of repeated records for those animals measured several times in their lifetime.

 

Hill Sheep Evaluation

• New Estimated Breeding Values will be launched for Ewe Mature Weight and Body Condition Score following work that generated new EBV for Ewe Longevity and Lamb Survival available in 2022 (Funded by the Hill Ram Scheme, run by HCC).
• Estimated Breeding Values for Faecal Egg Count (FEC) will be enhanced and published for several hill breeds following the inclusion of data collected in Autumn 2022
• New Estimated Breeding Values will be launched for IgA levels in blood serum (an indicator of parasite resistance)
• As above, EBVs for Maternal traits have been modified with the application of an updated model, but the impact will be relatively small.
• A small number of pedigree records have changed where genomic information has confirmed the original parents had been recorded incorrectly. This update will influence the EBVs for those animals.

 

In all three evaluations

• SRUC will start using a new version of the software that we use to calculate Accuracy Values. For well recorded traits, the impact on accuracy values for most of the animals in the evaluation won’t be noticeable. The biggest impact is a more conservative approach to the calculation of accuracy values for maternal traits in breeding lines that have a limited pedigree, such as new rams entering the evaluation for the first time. EBVs and Indexes are not affected by this change.