Murray Grey breeders set to benefit from the implementation of Single-Step BREEDPLAN

Murray Grey breeders are set to benefit from several major enhancements in the Murray Grey BREEDPLAN analysis later this year, with the implementation of Single-Step BREEDPLAN and a new Calving Ease model anticipated for release in the April 2025 analysis.

These enhancements will improve the predictive ability of the BREEDPLAN analysis, ensuring that Murray Grey BREEDPLAN is continuing to make the best use of data being collected by Murray Grey breeders across Australia, New Zealand, Canada, the UK and the USA.

What is Single-Step BREEDPLAN?

Unlike the current Murray Grey BREEDPLAN analysis, which only uses pedigree and performance information, a Single-Step BREEDPLAN evaluation will also utilise genomic (DNA) information to calculate EBVs. In this sense, genomic information is providing an extra source of information for the BREEDPLAN analysis to use.

There are two ways in which DNA information can provide additional information for the Murray Grey BREEDPLAN evaluation. Firstly, when a Murray Grey animal is genotyped, the analysis can then take account of each animal’s actual genetic relationship with all other genotyped animals in the population (see breakout box for more technical detail). Secondly, the analysis gains extra information by accounting for how the DNA information relates to the performance records for each trait in the analysis.

Murray Grey breeders should note that the use of genomic information as an additional data source to calculate EBVs does not diminish from the use of performance data in Murray Grey BREEDPLAN. Indeed, a reference population (animals with both performance data and genomic information) is critical to the ongoing success of Single-Step BREEDPLAN, and Murray Grey breeders are strongly encouraged to continue to collect performance data for all traits that are of importance to their and/or their clients breeding objectives.

What are the benefits of Single-Step BREEDPLAN?

There are several advantage of Single-Step BREEDPLAN that will be applicable for Murray Grey breeders. If animals are genotyped early in life, and their DNA information included in the Single-Step BREEDPLAN analysis, then this can “boost” their EBV accuracy. Having higher levels of EBV accuracy earlier in life means that Murray Grey breeders can make more informed selection decisions earlier in an animal’s life (e.g. for mating yearling heifers). In turn, this may assist to drive rates of genetic gain both in the individual herd and for the breed as a whole.

In addition, for Murray Grey breeders with smaller herds and/or undertaking ET programs, EBV accuracy levels are often limited by small contemporary group sizes even when pedigree and performance records are available. If calves are genotyped, however, they can accumulate additional information – and EBV accuracy – via their relationship to the wider genotyped and performance recorded population.

What about the new Calving Ease model?

The new Calving Ease model will include a number of improvements, including the implementation of a Single-Step Calving Ease analysis. This will be particularly beneficial for Murray Grey breeders who have low incidences of assisted calvings for their herds, as genomic information will provide an additional source of information for the Calving Ease analysis to utilise.

Additionally, there will be changes to how contemporary groups for Calving Ease are formed. As a result, there will be changes to the animals analysed for Calving Ease – some animals will no longer be analysed, while others will be analysed for the first time.

What changes can Murray Grey breeders expect?

Murray Grey breeders can expect to see changes to EBVs, associated EBV accuracies and selection indexes as a result of the introduction of Single-Step BREEDPLAN and the new Calving Ease model. In particular, genotyped animals that had a low EBV accuracy prior to the introduction of Single-Step will likely see the biggest increases in EBV accuracy following release of Single-Step BREEDPLAN, although the magnitude of EBV accuracy increases will vary by trait.

BREAKOUT BOX 

When an animal is genotyped, Single-Step BREEDPLAN takes account of each animal’s actual genetic relationship with all other genotyped animals in the population. This is demonstrated in Figure 1. Under a conventional BREEDPLAN (no genomics) analysis, the example animal is assumed to share 25% of its DNA with each of its grandparents (Figure 1A). However, genotyping reveals the true genomic relationship between this animal and each of its grandparents. The example animal shares more than 25% of its DNA with both its paternal granddam (red) and maternal grandsire (pink), and less than 25% of its DNA with both its paternal grandsire (blue) and maternal granddam (yellow; Figure 1B).

Figure 1. A) Conventional BREEDPLAN (no genomics) assumes that each animal shares 25% of its DNA with each of its grandparents. B) However, if the animals are genotyped, Single-Step BREEDPLAN takes into account the actual genetic relationship between an animal and its grandparents.