Africa's impressively horned Ankole cows are one of many threatened indigenous livestock breeds. A survey of cattle, pigs, goats, sheep and poultry in 169 countries found that native breeds are being supplanted by high-yielding commercial strains, which may not be as resistant to disease and drought.

“Valuable breeds are disappearing at an alarming rate,” says survey leader Carlos Seré, director-general of the International Livestock Research Institute in Nairobi. At a meeting this week of policymakers, breeders and livestock scientists, he called for the creation of gene banks to conserve sperm and eggs from rare breeds.

The survey adds to fears that damaging levels of inbreeding exist even among the most abundant commercial breeds. For example, the world's most widespread cattle breed, Holstein–Friesian, is thought to be almost exclusively descended from just a few dozen prized individuals owned by breeding companies.