Another animal with bovine tuberculosis has been found in a quarantined north-central Nebraska cattle herd.

State agriculture director Greg Ibach said Friday that authorities have given TB tests to the entire herd at the Rock County operation, but so far only one additional animal was diagnosed with the disease.

Tests after it was killed confirmed the diagnosis.

The first case was detected by a federal inspector at a slaughterhouse, before the animal was killed.

Ibach says both cows were bought at a Nebraska auction, but he couldn't yet say who placed them for consignment sale.

On Thursday at the Nebraska Ranch Expo in Bassett, Ibach plans to brief cattle producers on the tuberculosis outbreak -- the first since the early 1990s in Nebraska.