Indigenous cattle crossed with exotic dairy breeds are the backbone of smallholder dairy systems, which dominate milk production in many African countries and bring improved livelihoods to millions of poor farmers.
When breeding crossbred cows, the breed composition of the cow and the bull must be known in order to produce the right breed composition of progeny. Existing high density genomic assays based on 50,000 to 700,000 genetic markers can be used to determine an animal’s breed composition. Although they have high accuracy, they are too expensive to use routinely.
CTLGH researchers are therefore investigating whether a low density and cost effective genetic assay can be developed that would work across Africa in the field. A comprehensive assessment of African cattle has highlighted that there is a great diversity among breeds within a group, some overlap between groups and some significant misclassification of indigenous breeds. There is also a big difference between countries and regions related to the genetics of the indigenous populations.
The team has developed a new method for choosing an optimum set of genetic markers to form a small assay for breed composition. Although only 300-400 markers are used, it gives a high level of accuracy in all cattle populations tested across West and East Africa. Having a single assay that works across Africa will allow assay costs to be reduced significantly and encourage use in the field.