13 August 2021 by ScienceLink
Southern Africa’s Nguni, Afrikaner, Drakensberger and Bonsmara cattle are unique and well suited to the climate of southern Africa. UP researchers are using the history and favourable genetics of these breeds to increase productivity and food security.
By identifying which genes code for their most favourable traits, like growth and resilience, researchers can help farmers selectively breed more productive animals while conserving the features that make these breeds special.
“As average temperatures rise, we need animals that are adapted to heat, such as the Nguni and the Afrikaner, which have the potential to grow economies and reduce hunger,” she says. “We need to quantify that potential by using genetic sequencing data to find the genes associated with adaptive traits like resilience to heat stress.”
Southern Africa has about 150 recognised indigenous breeds well suited to the region’s hot and dry conditions.
The Nguni breed has a few ecotypes adapted to specific areas in southern Africa, including the Shangaan, Pedi, and Nkone. However, Prof Van Marle-Koster says that some of these ecotypes are in danger of extinction from indiscriminate crossbreeding, having less than 1 000 breeding individuals according to the Food and Agriculture Organisation (FAO).
“The Bonsmara breed has the most genotyped animals to date at 5 000 individuals, which is very limited as elsewhere in the world breeds such as Hereford and Angus have millions of animals genotyped,” she says.
To get a better picture of the genetic potential of these indigenous breeds, Prof Van Marle-Koster sought to trace their origins by going through over 2 000 years of southern African history.
“I think that this context of history is important as we often forget to tell actual stories in our science,” Prof Van Marle-Koster says.
According to the archaeological record, it took a long time for cattle to be raised in southern Africa’s punishing climate. The first traces of cattle in the region date back to around 2 000 years ago, whereas cattle in other parts of Africa were present more than 4 500 years ago.
Prof Van Marle-Koster hopes that the long history of cattle in the region can also be reflected in their genetic data.
For instance, they found that in the 17th century, Dutch settlers used Sanga cattle from the Khoekhoe, and selectively bred them as draught animals, which then brought about the Afrikaner breed.
So far, Prof Van Marle-Koster and her team have published their review in the Sustainability Journal detailing the known breeds and ecotypes of southern Africa, as they put plans in place to do genomic sampling in South Africa, Namibia and Botswana. With this work, the researchers will use the resulting genomic data to help farmers breed more resilient and productive cattle.
With a more detailed genomic picture identifying the unique breeds like the Nguni, Prof Van Marle-Koster’s research will be able to conserve these ecotypes from being crossbred out of existence, taking their adaptive traits with them.