Patron: His Majesty King Charles III

South Devon: first beef breed in the UK to incorporate genomic information in BREEDPLAN genetic evaluation.

With the release of results from their August 2022 BREEDPLAN evaluation, the South Devon Herd Book Society (SDHBS) has become the first beef breed using BREEDPLAN in the UK to incorporate genomic information in the calculation of Estimated Breeding Values (EBVs) and accuracy of their registered population.

 “This is truly an exciting time for the Society and our members”, says Caroline Poultney, breed secretary of the SDHBS. “Our investment in genotyping began some years ago, in the hope of developing genomic breeding values for calving ease traits. But it quickly became apparent that we could achieve much more return on our investment by adding our genomic information into our genetic evaluation”.

In June 2019, members of the SDHBS “committee” met in Kenilworth Warwickshire with Dr. Brad Crook, BREEDPLAN technical consultant for the SDBHS and Manager of the Genetics Research and Development team at the Agricultural Business Research Institute (ABRI).  “There’s so much more your members could accomplish with the data they’re collecting”, said Brad. “You have taken one step by starting the genotyping process and another step by talking about genomic breeding values. Why not take a huge leap forward and integrate everything into a Single-Step BREEDPLAN evaluation of the South Devon breed?”

 What is BREEDPLAN?

BREEDPLAN is an advanced modern genetic evaluation system developed in Australia by AGBU, a joint venture of NSW Department of Primary Industries and the University of New England, funded by Meat and Livestock Australia Limited. Developed specifically for beef cattle breeds, the BREEDPLAN service is provided by ABRI and represents the most widely used genetic evaluation service for beef cattle internationally. Over 60 different BREEDPLAN evaluations have been developed, representing over 14 million animals, almost 40 beef cattle breeds and at least 100 breed associations distributed across 14 countries.

BREEDPLAN calculates EBVs for a wide range of production traits important to beef breeding enterprises. EBVs provide an estimate of the animal’s genetic value, which in turn provide beef breeders with useful information to improve the genetics of their herd. The standard BREEDPLAN evaluation makes use of all available pedigree and performance data collected on the Society database, plus knowledge as to how each trait is expressed genetically within the recorded population, to calculate EBVs for each animal in that population. In preparation for the move to Single-Step BREEDPLAN, the SDHBS implemented an updated set of genetic parameters and models in May 2022. These new parameters were estimated by Brad using the SDHBS data, ensuring that all assumptions in the genetic evaluation were as closely aligned to the population as possible.

 What is Single-Step BREEDPLAN?

Single-Step BREEDPLAN adds a further source of information to the calculation of EBVs and accuracy, with genomic information incorporated simultaneously with pedigree and performance data. The analysis takes account of the genomic relationships that exist between all individuals in the genotyped population – which means actual calculated relationships are used rather than “average relationships” based on recorded pedigree.

“This is the technical bit that can sometimes be a little tricky to unpack”, explains Brad. “I like to put it this way. When we talk about two full sib bulls, we can correctly say they have the same sire and dam, receiving 50% of their genetic material from each parent. However, what we cannot correctly say is that each receives the same combination of genetic material from each parent. The mix of DNA from the sire – which copies of which positions on each chromosome - is random, and likewise for the mix of DNA from the dam. Unless they are identical twins – where one embryo has split into two – we expect full sibs to be different at the DNA level. They share their source of DNA in common, but not the actual mix of the DNA components.” In conventional genetic evaluation, the assumption is that “on average” these full sibs will have 50% of their genes in common. In a Single-Step BREEDPLAN evaluation, however, the actual proportion of genes in common is calculated and the true genomic relationships within the genotyped population are used to improve the accuracy of prediction of genetic merit.

“One of the key lessons we learned”, adds Caroline, “is that while genomics can add considerably to the accuracy of our EBVs, nothing is really gained overall without a corresponding commitment to performance recording. If we encourage our members to genotype their cattle, but we drop the ball on performance recording, then we just have lots of genomic information stored on our database with little opportunity for return on investment. That is why we are increasing our promotion of good performance recording practices – and completeness of performance recording – among our registered members.”

 More information on performance recording, genomics and Single-Step BREEDPLAN is available from the BREEDPLAN website (breedplan.une.edu.au).

 

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