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2019 Annual Upgrades to the Genetic Evaluation

Terminals-Analysis-change-cover-letter.pdf   Corriedale-Analysis-change-cover-letter.pdf  Maternal-Analysis-change-cover-letter.pdf

The LAMBPLAN and MERINOSELECT analysis are continually being developed to improve the genetic evaluation and supply the best tools possible to producers to help improve genetic gain across the sheep industry. Major updates to the evaluations are implemented once a year to minimise any disruption that may result from the changes. A summary of the analysis changes can be found below, more detailed documentation will be available closer to the changes being implemented. It is important to understand the enhancements that have been made to the analysis and why you may see some changes in the breeding values of animals as well as how these breeding values and indexes are being reported. All updates detailed below will be added to LAMBPLAN on the 1st May run and MERINOSELECT on the 7th of May.  

These enhancements are so that Sheep Genetics can deliver better breeding values on more animals back to you! 

This year the key developments are: 

  • Reproduction Research Breeding Values (RBVs) for maternal breeds. 

  • Genomic information being included for additional breeds. 
  • Reporting of inconsistencies between pedigree and genomic information back to breeders. 
  • The new Terminal Carcase Production Index and the phasing out of Carcase Plus and LAMB2020. 
  • The new Maternal Wool Production (MWP) index. 

  • New index documentation for all analyses 

 

Reproduction Research Breeding Values (RBVs) 

Breeds/Analysis Affected: Maternal analysis only – Coopworth, Border Leicester, Corriedales and Composite Maternal  

Type of Change: New breeding values 

Key Points: 

Number of Lambs Weaned is the primary trait used in selection of reproductive performance, however this trait is a compound trait that combines many stages of the reproductive cycle

There are now 3 new component traits available that will be released as RBVs. These are conception (con), litter size (ls) and ewe rearing ability (era)
This gives breeders the opportunity to target the component traits of reproduction that they are interested in
There will also be additional traits released for Maternal Behaviour Score (MBS) and Condition Score (CS)

Detail:

The 3 new component traits for reproduction will be available for both yearling and adult stages where yearling traits are reported with a “Y” in front of the trait abbreviation (e.g.  YCON). These traits will be available in a unique set of reports that are sent out with the analysis results and will be reported on the website in purple, as they are RBVs. In addition to these component traits maternal behaviour score and condition score will also be reported as RBVs on the website. Please note that these are RBVs and in due course when developed into ASBVs might be subject to some change. Furthermore, the genetic linkage between flocks for some traits is lower than ideal and more confidence should be placed on comparisons within flock rather than across flocks.

The definitions of the new traits are outlined in the table below:

Trait

Abbreviations

Unit of Breeding Value

Trait Description

Example

Conception

YCON/CON

Ewes pregnant per ewes joined

The ability of a ewe to get in lamb in comparison to all the ewes in the same joining event.

Sires that have a higher conception breeding value will produce daughters that have a higher conception rate.

Litter Size

YLS/LS

Lambs per litter

The number of the foetuses a ewe has in comparison to all the ewes that got in lamb.

Sires that have a higher litter size breeding value will produce daughters that give birth to more lambs.

Ewe Rearing Ability

YERA/ERA

Lambs weaned per lambs born

The ability of the ewe to rear the lambs that she gives birth to.

Sires that have a higher ewe rearing ability breeding value will produce daughters that rear more of their litter.

Maternal Behavior Score

MBS

Score

The raw trait for maternal behavior score is measured on a 1 to 5 scale. Where a ewe with a 1 score does not move from the birth site of the lamb during tagging, therefore a lower breeding value is desirable.

Sires with more negative breeding values will produce daughters that do not move as far from the birth site.

Condition Score

CS

Score

The condition score of the ewe at joining.

Sires with a more positive breeding value will produce daughters that have a higher condition score at joining.


Genomic Information for Additional Breeds 

Breeds/Analysis Affected: Composite Maternal, Coopworth, Corriedale, Dorper, White Dorper, Hampshire Down, Southdown, Suffolk, Texel. 

Type of Change: Additional information being used in the analysis. 

Key Points: 

  • Until now the only breeds that have had genomic information included in the analysis are Border Leicester, White Suffolk, Poll Dorset and Merinos. 

  • Technical advancements in the analysis have now meant that genotypes from some other breeds can be included in the analysis. 

  • For many of these breeds the additional benefit from genotyping their animals will be very minimal. 

Detail: 

The breeds listed above are now able to submit genomic data that will be used in the evaluation where previously genotypes from these breeds have been excluded. However, for most of these they will receive little to no benefit from genomic information now being used in the evaluations. This is because there are not enough animals in the reference population (animals with a genotype and a phenotype) that underpins the genomic evaluation.  

These breeds will also be required to test on a denser platform than the 15K platform that White Suffolks, Poll Dorsets, Merinos and Border Leicesters use.  If you are one of these breeds that are interested in genotyping to develop a reference population, please contact Sheep Genetics for more information and advice about the density of platform to use.  

Reporting of inconsistences between pedigree and genomic information 

    Breeds/Analysis Affected: All breeds with genomic information being used in the evaluation. 

    Type of Change: New report. 

    Key Points: 

    • The genetic evaluation now uses information on animals’ relationships from both pedigree information supplied by breeders through their software and if available, genomics (note: genomics does not refer to DNA parentage). 

    • Sometimes there are discrepancies where the sire or dam listed in the pedigree of the animal does not match with the genomically informed relationships. 

    • There is now a new report where these inconsistences between pedigree and genomic information will be reported to breeders. 

    Detail:  

    Attached to the analysis results email there will be an additional PDF that outlines any inconsistences between pedigree and genomic information. Where possible the correct parent will also be recommended (if the potential parent also has a genotype). It is advised that breeders carefully look through this document to determine the cause of the errors and if the suggested parent is possible. It is important that the breeder confirms the mistake and it is their responsibility to correct it. There is documentation on the analysis updates page that describes how to interpret these reports.  

      

    The new Maternal Wool Production Plus (MWP+) Index 

      Breed/Analysis Affected: Maternal – in particular Corriedales and SAMMs. 

      Type of Change: New index. 

      Key Points: 

      • The Dual Purpose Dollar (DP$) index was out-of-date and was therefore reviewed. 

      • The Maternal Wool Production Plus (MWP+) is the new index that will replace DP$. 

      • MWP+ has a focus on improving wool quality and quantity whilst simultaneously improving reproduction and carcase traits.  

      Detail: 

      Maternal Wool Production Plus (MWP+) is the new replacement index for the Dual Purpose $. It has a focus on improving wool quantity and quality, whilst also focusing on growth and reproduction as key traits in the index. This will be the primary selection index for Corriedale and SAMM breeders as well as for maternal breeders that have a strong focus on wool quality. The index will be reported on the maternal search site as well as on the specialised search pages for Corriedales and SAMMs. 

       

      The new Terminal Carcase Production (TCP) Index and the phasing out for Carcase Plus and LAMB2020 

      Breed/Analysis Affected: Terminal. 

      Key Points: 

      • Carcase Plus and Lamb2020 indexes were designed to select solely for lean meat yield and as a result are reducing eating quality. Carcase Plus, when used with genomics declines eating quality at a faster rate. 

      • Carcase Plus and Lamb2020 are over 15 years old and now out of date indexes.  

      • Terminal Carcase Production is the new index that focuses on improving the key production traits of growth and muscle whilst simultaneously maintaining eating quality. 

      • LAMB2020 no longer exists, whilst Carcase Plus will be available for this year only to assist in the transition period . 

      • Resources will be available to assist breeders adapt to the changes. 

      Detail: 

      The TCP index continues to deliver genetic gain that reflects the current supply chain price signals. The predicted response for muscling and growth will continue to increase, however overall consumer liking will cease to decline. The emphasis on each trait is balanced by its relative economic value to a terminal lamb production system, making Terminal Carcase Production an economic index. 
      It is worth noting that TCP is in different units to Carcase Plus. This means that the average index values and the variation between animals will be different. Therefore, it is important that both ram breeders and commercial ram clients re-benchmark themselves using the new index. 

      Sheep Genetics recognises that phasing out Carcase Plus will be a significant change for the industry. Therefore, for the period between April 2019 and April 2020 Carcase Plus will still be available. TCP will replace Carcase Plus as the primary index on reports but it will still be available this year for ram sale catalogues and to assist in the transition to TCP. It is strongly encouraged that ram breeders begin working with their ram clients this year whilst both indexes are available to transition to the new index, as it will not be available for the 2020 ram selling season. Furthermore, we will be providing resources for industry to use. These include: 

      • Flyer for stud breeders – outlining the changes in greater detail. 

      • Flyer for commercial ram buyers where changes are outlined that breeders can use in their communication. 

      • Updated commercial ram buyer index documentation so that the indexes available are more clearly outlined (please see point 6 for more detail). 

      • Webinar – this video will be available online as a resource that clients can be referred to. 

       

      New Index Documentation 

      Breed/Analysis Affected: All. 

      Type of Change: New documentation. 

      Key Points: 

      • The previous index documentation on the Sheep Genetics website was not consistent across analyses. 

      • In addition, the previous documentation did not meet the needs of both the commercial ram buyer and the seed stock breeder. 

      • This documentation has now been redeveloped so that: 

      1. The messaging is consistent across all documents 

      2. There is a commercial ram buyer version and a seed stock breeder version. 

      Detail: 

      The updated index documentation will be housed on the Sheep Genetics website under the “Getting Started” tab.  

      The commercial version of the document is aimed at allowing commercial breeders to identify what index best suits their production system so that they can use it in their ram purchasing decisions. There will also be a section on how to best use an index in ram buying decisions. This documentation will be a useful resource for seed stock breeders to use in their communication with clients. 

      Furthermore, there will new documentation that outlines more detail about the trait contribution for the indexes as well as the recording assumptions for each of the indexes that is targeted at Sheep Genetics clients. This will allow them to best identify a selection index that matches their breeding objective.