WSDA Blog

In late September, the Washington State Department of Agriculture (WSDA) was notified that a two-and-a-half-year-old Jersey cow originally from Washington had tested positive for bovine tuberculosis (TB) in a New Mexico dairy herd. The cow’s official identification number traced back to a cattle broker facility in central Washington, prompting WSDA to act immediately to protect the state’s livestock industry and preserve its TB-free status.

The New Mexico Livestock Board reported that the cow’s ID number could not be found on any Certificates of Veterinary Inspection (CVIs) from the Washington broker, making her movement history difficult to trace. The first record of her ID appeared when she was scanned at the New Mexico dairy during a routine pregnancy check on February 1, 2025. The producer there believes she likely arrived in late January 2025.
 

WSDA’S immediate response

As soon as WSDA was notified of the positive case on September 24, the agency contacted the Washington broker and placed a hold order on all cattle at his two facilities. An epidemiological investigation began right away to determine the cow’s movements and potential exposure risk.

The investigation found that the broker routinely purchases young dairy cattle – typically between eight and eighteen months old – from various sources, including local dairies, Washington livestock markets, and dairies in Idaho and California. He then breeds these heifers and sells them when they are close to calving. Because he buys and sells frequently and across multiple states, accurate animal identification and recordkeeping are critical to traceability.

Even though this producer is fully cooperating with the investigation he does not retain detailed records of purchases, sales, or RFID tag placements. That lack of documentation made it impossible to confirm when the infected cow entered or left his facilities.
 

The role of animal health records and identification

WSDA’s Animal Health Program exists for exactly this reason – to help protect Washington’s ranchers, dairy producers, and the broader livestock industry by managing disease control, reviewing animal health documents for interstate movement, tracking reportable diseases, and collaborating with industry partners. The program uses tools such as RFID tags, official identification, and movement records to allow investigators to quickly trace animal movements during disease events.

In this case, livestock identification plays a vital role in helping WSDA track and contain potential risks while maintaining confidence in Washington’s tuberculosis-free status.

Quarantine and herd testing 

Because the exact movement of the infected cow could not be confirmed, WSDA placed both of the broker’s facilities under quarantine out of an abundance of caution. The herds at these sites are not considered infected, but rather classified as source herds for a cow that later tested positive out of state.

To verify that Washington’s livestock remain TB-free, WSDA conducted whole-herd tuberculosis testing at both facilities. Meanwhile, whole genome sequencing performed by the National Veterinary Services Laboratory (NVSL) indicated that the cow most likely contracted the disease while in New Mexico, not in Washington.
 

Testing progress and early results 

As of November 1, WSDA identified 2,090 head of cattle between the two quarantined premises.

• 2,059 cattle underwent Caudal Fold Tuberculin (CFT) testing.
• 31 head could not yet be tested because they had recently been tested elsewhere. These animals are being held separately, marked with blue ear tags, and will be retested later in November. 

Among the 2,059 cattle tested, 19 suspects were identified – well within the U.S. Department of Agriculture’s (USDA) expected 1–3% suspect rate for uninfected herds. Blood samples from these 19 animals were sent to NVSL for gamma interferon testing, and each animal received a green numbered tag for tracking.

When suspects are found in CFT testing, secondary TB tests such as the Comparative Cervical Tuberculin (CCT) test or gamma interferon test are used to determine whether the animal is truly infected. Negative results clear the herd; positive results require additional testing or euthanasia with laboratory analysis to confirm infection. 

Next steps

WSDA is currently awaiting gamma interferon results from NVSL. Regardless of the test outcomes, WSDA plans to euthanize and necropsy all 19 suspects as a precautionary measure to ensure they are truly negative and to maintain the state’s TB-free status.
Next steps include:

• Completing CFT testing on the 31 head that could not yet be tested — expected in late November.
• Conducting necropsies on the 19 suspects — currently delayed by the federal government shutdown but anticipated to be finished before the end of the month.

Maintaining Washington’s TB-free status 

Washington remains committed to protecting its livestock industry and maintaining its tuberculosis-free designation. WSDA continues to work closely with the USDA and NVSL to ensure accurate testing, thorough investigation, and transparent communication with industry partners.

Bovine tuberculosis is a serious but rare disease in U.S. cattle herds, and cases like this highlight the importance of traceability, cooperation, and rapid response in protecting both animal health and the agricultural economy.

A big shoutout to all the staff that helped with the TB trace events: 

Dr. Hutton, Dr. Smith, Jodi Jones, Kelsey Lindstrom, Rachel Burkhart, David Hecimovich, Dave Clement, Rick Daugherty, Bryant Blake, Brennan Kimbel, Keeley Teel, Briley Bock, Kayla Slaybaugh, Dr. Itle, Kerrie Love
 
For more information on the great work from this team, visit our Livestock Identification Program webpage.