Nebraska Agriculture Director Greg Ibach provided an update today on the state’s ongoing epidemiological work associated with Nebraska’s bovine tuberculosis (TB) case.

“We continue to make positive progress in several areas of the epidemiological investigation,” Ibach said, “and we are pleased with the results, to date, that show no additional positive TB cases after 20,000 animals tested.”

The Nebraska Department of Agriculture (NDA) announced on June 1, 2009, that a cow from a Rock County beef herd had tested positive for bovine TB. A second cow from that herd later also tested positive for the disease. Since that time, NDA has been conducting an epidemiological investigation, which involves locating any cattle that may have been pastured next to the initial affected herd during the past two years, as well as tracing cattle movement into and out of that herd. To date, eight herds remain under quarantine in seven counties.

Ibach said teams have completed testing of “fenceline herds,” those animals known to have been pastured next to the initial affected herd during the past two years. NDA and United States Department of Agriculture (USDA) staff also continue to review previous movement of animals into and out of the initial affected herd. This tracing could result in some additional testing as NDA and USDA attempt to complete the epidemiological investigation, Ibach said.

“We have a few herd owners that we need to visit with yet. Once the associated epidemiological work is complete, that phase of the investigation will be finished,” Ibach said.

NDA has been working closely with USDA regarding disposition of the herd that contained the two infected cattle. That herd remains under quarantine in Rock County. USDA protocol at present calls for either depopulation of the herd or extensive testing of the herd over multiple years.

However, USDA’s Animal and Plant Health Inspection Service (APHIS) Veterinary Services (VS) leaders have been having extensive discussion recently about the federal TB protocol and the long-term vision for animal health in the United States.

“Nebraska is working with USDA as they develop alternatives to address the issue of bovine tuberculosis across the United States,” Ibach said. USDA recently published in the Federal Register a document outlining their new, proposed plan for addressing TB. It will focus on several steps, including enhanced surveillance, alternative control strategies, and a transition from a state classification system to a science-based zoning approach for disease risk.

Ibach said NDA and USDA are utilizing a new “test-and-remove” strategy on the Nebraska initial affected herd that is based on modeling developed by APHIS-VS. Ibach said under this model, the Rock County herd will undergo a series of whole herd testing every 60 days until the test results indicate a statistical confidence that the herd is free of TB. Depending on the testing outcome and other factors, the herd could be off of quarantine next spring.

“This testing protocol provides a statistically- and scientifically-based alternative to depopulation, which decimates a producers’ livelihood. This option is particularly important in a state like Nebraska, where many breeders have genetic lines that have been developed for over a century and passed down through several generations.

“This testing protocol, our epidemiological investigation, and our state’s slaughter surveillance together should provide assurance that the risk of bovine TB in Nebraska’s beef herd is extremely small,” he said.

Nebraska’s current USDA TB-free status will remain in place as the additional testing is conducted.

NDA will continue to update test result information, counties with herds that are quarantined and other relevant TB information on its web site at www.agr.ne.gov, under the bovine TB button on the right side of the home page. However, this information will now only be updated as new data becomes available.

Ibach noted that most of the current quarantines shown on the web site chart represent cattle that have been quarantined to feedlots and are destined for slaughter. They will be inspected for TB by federal officials as a routine part of the slaughter process.