LINCOLN, Neb. (AP) — Nebraska agriculture officials say they are still waiting on the results of roughly 1,600 bovine tuberculosis tests, so it's not known whether any new cases of the disease exist.

The state says the results of tests performed between July 6-12 weren't ready in time for Monday's scheduled update. Officials expect those test results to be ready by the middle of this week.

Besides the delayed tests, a total of 6,200 cattle have tested negative since two cases of bovine TB were found in north-central Nebraska in a RockCounty herd.

As of Sunday, 27 herds in 14 north-central and eastern Nebraska counties have been quarantined. Most of those herds are quarantined because they had some contact with the infected herd.