The German government has ordered the slaughter of more than 1,000 cattle as part of its fight against mad cow disease.
It is the first herd to be killed since the disease was detected in cows in Germany last year.
The secretary of state for Saxony Anhalt says 1,012 cattle from one farm will be destroyed after veterinarians determined one of the animals in the herd was infected with the disease.
Germany has so far detected 19 cases of mad cow disease, the common name for bovine spongiform encephalopathy, or BSE, a brain-wasting ailment that scientists believe was spread by recycling meat and bone meal from infected animals back into cattle feed.
Officials say they had to destroy the entire herd because all the cows in the farm in Saxony Anhalt may have received the same feed. Farmers in Germany have protested against slaughtering whole herds.
German officials have declared the country mad cow-free until the first case emerged in November. The country's agriculture and health ministers resigned earlier this month amid accusations they had mishandled the crisis.