15 December 2023
New single-step analyses have been introduced for Brahman breeders in South Africa, Namibia and Zimbabwe, giving them access to Breedplan’s estimated breeding values that include genomic (DNA) information.
A single-step analysis (single nucleotide polymorphisms, or SNP) uses concurrent pedigree, performance and genomic information. The evaluation considers each animal’s genetic relationship with all other genotyped animals. The Brahman reference population includes animals with genotypic (SNP) and phenotypic data (performance records) for each specific trait.
The Brahman Breed Improvement Forum, established in April 2013, paved the way for the success South African Brahman breeders are now experiencing, which is the result of years of hard work.
The Brahman community was introduced to genomics in 2015 when the Brahman Society joined the Beef Genomics Programme. This marked the beginning of building a reference population consisting of cattle with a genotypic measurement for one or more traits, as well as genotypic heifers with well-documented offspring.
A reference population must also be as representative as possible of the gene pool, concentrating on animals with a chance of contributing to future generations, and including phenotypes of all the important traits or trait groups (to maintain balance in selection). If different environments are relevant, data from them are needed.
Preserving the oldest breeding material
To preserve the oldest breeding material in the reference population, four influential heifers were chosen for whole-genome sequencing. They were included in the list of 50 animals representing 50% of the total genetic variation of the South African Brahman population. These four bulls – 78WD’S, BBBB 70 114, BPM 90 307 and MAS 90 15 – are therefore the most influential animals.
Dr Brad Crook, Breedplan’s consultant on genetic research and development, says collaboration between the Brahman societies of South Africa and Namibia, and Brahman breeders registering their animals with the Zimbabwe Herd Book, has led to this well-structured reference population.
Most of these cattle possess traits that are important for the breed, such as feed efficiency, fertility and cow weight. These traits are increasingly important in developing breeding programmes for sustainable beef production. Breeders can access this reference population by genotyping their own animals to achieve greater accuracy for these important traits at an earlier age.
If young animals are genotyped, they can achieve higher accuracy for estimated breeding values at a younger age – especially for traits that become apparent only later in an animal’s life – than is possible under a conventional Breedplan model. This leads to greater accuracy in selection decisions.
According to Crook, breeders with a small herd are often limited by small contemporary groups, even if pedigrees and performance records are available. When calves are subjected to genotyping, breeders obtain additional, accurate information from their relationship with the larger genotyped and performance-tested reference population.
