It’s been more than two years since HPAI was first detected in dairy cattle. But two recent cases are serving as a reminder that farmers can’t let their guard down when it comes to biosecurity.
The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) confirmed Oct. 8 that two Washington dairy herds tested positive for highly pathogenic avian influenza (HPAI) H5, marking the first confirmed detections in the state’s cattle.
Both herds had previously tested negative through routine surveillance under the National Milk Testing Strategy but were tested again after cattle showed clinical signs consistent with avian influenza. APHIS National Veterinary Services Laboratories confirmed the detections through polymerase chain reaction (PCR) testing.
Since the outbreak began in March 2024, HPAI has been detected in dairy cattle across 19 states, with fewer states reporting cases in 2026. APHIS and the Washington State Department of Agriculture are investigating the new detections and conducting additional testing to better understand how the virus reached the herds and prevent further spread.
Biosecurity Plans Need Regular Attention
Even as HPAI detections have slowed in 2026, the new Washington cases show the virus is still out there. Keeping up with biosecurity takes regular attention, from managing who comes onto the farm to keeping equipment and animal areas clean.
USDA’s eradication strategy remains unchanged, and APHIS continues to recommend enhanced biosecurity measures on all dairy farms to help prevent the virus from entering or spreading through a herd.
Farm Journal research presented at the 2025 MILK Business Conference found 68% of dairy farms with at least 250 cows reported having a biosecurity plan. But having a plan and keeping it current are two different things: 34% said they did not review their plans regularly.
The survey also found gaps in farm security. More than 20% of surveyed dairies did not secure access to barns, while 38% did not restrict access to feed-storage areas. Sixteen percent did not monitor visitor access, and 33% used camera surveillance to oversee their facilities.
Kirk Ramsey, a professional services veterinarian with Neogen who reviewed the survey results, says farms need to pay attention to how biosecurity works in daily practice.
“We need biosecurity efforts to be more impactful at the ground level. Not only to prevent major outbreaks, but to even protect employees and families from the things being taken home every day,” Ramsey says.
Producers can start by reviewing who enters the farm and where visitors can go. Cleaning equipment and controlling movement between animal groups also help reduce the chance of spreading disease.
USDA offers financial assistance to help dairy farms strengthen biosecurity and offset costs associated with HPAI.
Keep Other Diseases on the Radar
HPAI is not the only disease dairy farmers need to watch. On Sept. 29, Wisconsin officials confirmed epizootic hemorrhagic disease (EHD) in non-lactating dairy cattle in Waukesha County. It was the state’s first confirmed cattle detection since 2013, amid an outbreak affecting white-tailed deer across southeastern Wisconsin.
The affected cattle were young, pasture-raised heifers with mild hoof lesions. The owner worked with a veterinarian to collect samples for testing, which identified the EHD virus. EHD is spread by biting midges and is separate from HPAI.
The Wisconsin detection is another reason to contact a veterinarian when cattle show unusual signs of illness. Prompt investigation can help identify the cause and determine what action is needed.
Animal purchases also deserve careful attention. Derek Nolan, a dairy education and extension specialist with the University of Illinois Urbana-Champaign, recommends involving veterinarians before bringing new cattle onto a farm.
“Before you purchase animals, have a vet-to-vet conversation,” Nolan advises. “Inquire about animal testing and herd-level tests. Review physical health, milk quality and past health records.”
Make Biosecurity Part of the Routine
With HPAI still turning up in dairy cattle more than two years after the outbreak began, producers should keep biosecurity plans current and watch for changes in their herds. Early signs can be easy to miss, so employees should know what to look for and report concerns to the herd veterinarian promptly.
Symptoms of HPAI in cattle include:
- Drop in milk production
- Loss of appetite
- Changes in manure consistency
- Thickened or colostrum-like milk
- Low-grade fever
Producers should also pay attention to changes in how cows look or act, particularly when several animals show similar signs. If HPAI is suspected, contact a veterinarian to discuss next steps and testing. Continue following state and federal guidance on reporting and biosecurity to help limit the risk of spreading the virus.
