The world’s food supply is increasingly dependent on a small and narrowing list of highly engineered breeds: the Holstein, the Large White pig and the Rhode Island Red and Leghorn chickens. There’s a risk that future diseases could ravage these homogeneous animal populations. Poor countries, which possess much of the world’s vanishing biodiversity, may also be discarding breeds that possess undiscovered genetic advantages. But farmers say they can’t afford to wait for science. And so, on the African savanna, a competition for survival is underway.
