Herefords join move to single-step genetic evaluation

Beef Central, 07/11/2017


THE Hereford breed has become the second beef cattle breed in Australia to deliver a single-step genetic evaluation to members.

This program will enable Hereford producers to more accurately estimate the breeding values of their cattle. This means that producers have more information when it comes to selecting animals to benefit the genetics within their herd, and in turn this will deliver greater genetic benefit for the Hereford breed as a whole.

Herefords Australia, in conjunction with Animal Genetics and Breeding Unit (AGBU) and ABRI have implemented a multi-country single-step genetic evaluation for the full multi-trait BreedPlan analysis, including fertility, growth, and carcase traits.

The first Estimated Breeding Values to be calculated using the new single-step system were released to members on 27 October.

“This is a significant and positive step forward in the genetic evaluation of the Hereford breed in Australia, New Zealand and Namibia,” ABRI BreedPlan spokesman Brad Cook said.

The use of single-step integrates genomics into traditional genetic evaluation, allowing for more accurate calculation of EBVs.

Traditionally, EBVs used only pedigree data to estimate the genetic similarity of animals, however the new single-step evaluation analyses all genomic, pedigree, and performance data in the one model.

This genomic data is more accurate in measuring the relatedness, and therefore the genetic similarity of animals. In essence, the new single-step analysis relies more on genomic relationships than pedigree relationships, leading to a more accurate EBV.

As a result, genomic relationships will become far more valuable than the traditional pedigree, and genotyping will play a larger role in the integrity of genetic evaluation for the Hereford breed.

Dr Alex Ball

Herefords Australia’s Dr Alex Ball said the introduction of single-step provided world-leading genetic analysis for the breed, and allowed breeders to make more informed selection decisions, which will hopefully translate into faster rates of genetic gain.

Over the last 12 months, Herefords Australia breeders have made significant investment in the genotyping of animals. As a result, the number of genotyped animals in the current single-step analysis is more than 3500, of which more than 1000 are sires.

For many key genetic traits, an animal with a genotype can be expected to have a GE-EBV calculated at around 40pc in accuracy. For most traits this is an improvement of 10-15pc in accuracy.

The implementation of the new system of genetic evaluation will represent a major platform change for livestock breeding, Dr Ball said.

In order to obtain the full benefit of the single-step analysis, seedstock breeders would need to have animals with a minimum of a low density genotype, available through any of the new Herefords Australia DNA test bundles.

However, as pedigree information is still used, all animals will see some impact from the new analysis. Importantly, the highest accuracies will be generated for those animals which are genomically related to a reference population (in this case, the Trans-Tasman Hereford BreedPlan database and the Herefords Australia BIN program).

The Brahman breed announced its adoption of single-step genetic evaluation in May, and Angus breeders have also flagged their intention of adopting the model.


Source: Herefords Australia


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