Genomic breeding values

by Dr Delana Davies, Farming Connect Knowledge Exchange Hub ThE first genomic breeding values for use in the UK beef industry have now become available. The pig and poultry sectors have seen rapid genetic progress over successive generations through DnA testing, and the availability of genomic values for the dairy industry in the UK since 2010 has resulted in a step change in production parameters for the early adopters. What are GEBVs? genomic Breeding Values (gEBVs) are breeding values derived from information in an animal’s DnA. Whilst Estimated Breeding Values (EBVs) are based on measured performance (e.g. growth rate) on farm and within a contemporary group, gEBVs are calculated by compiling information both from the animal’s performance and its DnA. Further animals’ DnA can then be compared and evaluated against this library of DnA and performance records from thousands of animals to accurately predict breeding merit. gEBVs for a range of new carcase traits are now available for all Limousin bred cattle. They represent estimates of genetic merit using new and independent sources of information; visual image analysis (VIA) records on individual carcase cuts from selected abattoirs and information from a vast pool of Limousin DnA. This information is combined to produce breeding values that indicate an individual animal’s strengths and weaknesses for each trait. When the additional value of all the cuts is multiplied up, it equates to an estimated difference of around £100/calf between high genetic merit sires and low genetic merit sires. half of the calves’ genes come from its sire and assuming all things are equal, this means the sire with superior carcase genes has the ability to produce calves worth £50- £75/head more than calves by sires with the poorer carcase genes. On a wider level, further advantages of gEBVs include: • Data from independent sources: Use of independent abattoir records and animal DnA represents a significant step forward in the data used for genetic evaluation. On farm recording will remain important however, as gEBVs require ongoing recalibration. • Speed: gEBVs can be obtained shortly after a calf is born enhancing selection opportunities. • Improved accuracy: for many traits that have low heritability or are difficult or expensive to measure, gEBVs will offer higher levels of accuracy. • Lower cost: Because accuracies are enhanced much more quickly using gEBVs there can be less cost involved. • All owners of Limousin bred cattle can gain GEBVs: A significant difference between an EBV and gEBV is that the former relies on the collection of performance records across groups of animals. For a gEBV, all that is required is the DnA sample and the identity of the animal. It offers commercial producers significant opportunity in assessing current and future sires and replacement heifers. Professor Mike Coffey from SrUC said: “This is a game changer for the beef industry. genomic selection will bring large and rapid benefits to beef breeders and processors in the same way as it has for the dairy industry. It will enable the UK beef sector to remain internationally competitive and will provide a platform for the future that will include other economically important traits such as feed intake and meat quality.”

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