Release of a Single-Step BREEDPLAN Analysis for the Brahman Breed Across Southern Africa

Nov 2023

Brahman breeders across Southern Africa now have access to BREEDPLAN EBVs that include genomic (DNA) information, following the release of the November 2023 Brahman BREEDPLAN analysis for Namibia, South Africa and Zimbabwe. This significant enhancement uses a methodology known as Single-Step.

The introduction of Single-Step BREEDPLAN for the Brahman Cattle Breeders’ Society of Namibia, the Brahman Cattle Breeders’ Society of South Africa and Brahman breeders recording with the Zimbabwe Herd Book has required a considerable amount of research, testing and validation to ensure the genotypes are used as correctly and accurately as possible.

Dr Brad Crook, BREEDPLAN Manager Genetics Research and Development, explains. “Collaboration among the three Brahman societies has resulted in quite a well-structured reference population, where most genotyped animals are also well-recorded for traits of importance to the Brahman breed in Southern Africa. This includes feed efficiency, fertility and cow weight traits, all of which are becoming increasingly important in developing breeding programs for sustainable beef production. Brahman breeders can tap into this reference population by genotyping their own cattle and gaining greater accuracy on these important traits at earlier ages in the herd.”

What is Single-Step BREEDPLAN?

The Single-Step BREEDPLAN evaluation utilises pedigree, performance, and genomic information simultaneously. The evaluation takes account of each animal’s actual genetic relationship with all other genotyped animals, including those in the reference population. The reference population is the set of Brahman animals that have genotypes (SNP data) and phenotypes (performance records) for each particular trait.

SNP data is now being used along with pedigree and performance data to calculate BREEDPLAN EBVs and accuracy “in one step”. This applies to all traits in a multi-trait model combining birth, growth, fertility and carcase traits. As such, SNP data provides additional information in these calculations by accounting for the true genomic relationships among animals and how the SNP information relates to the performance records for each trait in the analysis. An important feature of the Single-Step BREEDPLAN approach is that complete use is made of the high density of genotypes recorded by Brahman breeders.

What are the advantages of Single-Step BREEDPLAN?

There are advantages that come with genomics and the Single-Step BREEDPLAN model. When young animals are genotyped at an early stage in life, they can achieve higher levels of EBV accuracy earlier in life – especially for traits expressed later in life – than is possible with a conventional (non-genomics) BREEDPLAN model. This equates to greater accuracy of selection decisions, at an earlier stage in the growth of animals, for Brahman breeders across Southern Africa.

Furthermore, for breeders with small herds, 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 accuracy – via their relationship to the wider genotyped and performance recorded population.

Ultimately, the implementation of Single-Step BREEDPLAN for the Brahman breed across Southern Africa provides members of the Brahman Cattle Breeders’ Society of Namibia and the Brahman Cattle Breeders’ Society of South Africa, as well as Brahman breeders recording with the Zimbabwe Herd Book, with greater returns on their investment in the genotyping of seedstock cattle.