INDIANAPOLIS – Hoosier dairy producers are being urged to remain vigilant after bird flu was detected in two dairy herds in Newton County in late October.

Milk from both herds was tested at an out-of-state processing facility and the positive results reported to the Indiana State Board of Animal Health (BOAH), the agency announced Nov. 2. The milk was tested as a part of the National Milk Testing Strategy (NMTS) for highly pathogenic avian influenza (HPAI). The strain was identified as H5N1.

The herds are from operationally connected farms and were sourced from an out-of-state farm, Denise Derrer Spears, BOAH communication director, told Farm World. Genetic sequencing of the virus confirmed the link to an out-of-state farm, she said.

“This finding was unexpected, as BOAH has not identified any cases since we began monitoring the milk supply in Indiana under USDA’s NMTS for about two years,” she said.

“Overall, producers need to know that the virus is still out there and in circulation in various parts of the country. Weekly reports from the USDA show new cases of H5N1 on dairy farms cropping up across the United States. Farmers need to remain diligent about biosecurity and preventing introduction.”

The USDA’s Animal and Plant Health Inspection Service (APHIS) said the detection does not pose a risk to consumer health or affect the safety of the commercial milk supply. The U.S. Food and Drug Administration is confident that pasteurization is effective at inactivating the HPAI virus and that the commercial, pasteurized milk supply is safe, APHIS said in a release.

The detection in the Indiana herds was made in another state, then reported to BOAH, Spears said. A change was made this summer in how the milk is collected under the NMTS for monitoring – a shift to sampling at processing, instead of the farm, she said.

“The challenge – as borne out by this detection – is that farms that ship out milk out of Indiana for processing are monitored as part of another state’s NMTS surveillance efforts,” she explained. “That can delay reporting to BOAH, as the state testing the milk at the processing facility must obtain records about what farms contributed to the bulk storage silo at the site, then report back to the states-of-origin for followup.

“But the trace-notification process works, so we are confident cases will be reported to us if and when they arise.”

The NMTS was announced by USDA in late 2024. The strategy is a nationwide surveillance plan to identify cases of H5N1 on dairy farms, BOAH said, thereby allowing states to verify the presence or absence of the disease. The NMTS is a five-stage program designed to detect the H5N1 virus in unpasteurized milk, BOAH said.

The Newton County farms will be under quarantine until they achieve negative tests of the milk collected at the farm for two consecutive weeks, Spears said. This will establish that the cows are recovered and no longer shedding the virus, she added.

Cattle can recover from the H5N1 influenza virus with supportive care and time, Spears said. Poultry, on the other hand, become very ill, very quickly, leading to death, she noted. That’s a major difference in how the same virus can impact two different species, Spears said.

The H5N1 finding changes Indiana’s unaffected state status, BOAH said. Under USDA interstate movement requirements for affected states, all lactating cows – including dairy-beef crosses – must have a negative H5N1 test before leaving the state.

As of press time, “BOAH does not have evidence this is a widespread issue within Indiana,” Spears said. “Ongoing monitoring of the milk supply under the NMTS has not found any other Indiana cases.”

Patrick Hash, director of agricultural affairs for the American Dairy Association Indiana, said pasteurized milk remains safe. Producers should review their biosecurity practices with their veterinarian and employees, he said in a release.

Farms should limit non-essential visitors, use dedicated boots and clothing, and follow cleaning and disinfection procedures for equipment and vehicles, Hash said. A veterinarian should be contacted promptly about changes in cow health or milk production, he said.

Hash offered some tips on how to respond if someone asks about the situation, He recommended that producers keep their responses simple and focused on what they know.

One suggestion from Hash would be for a producer to say, “Keeping our cows and the people who care for them healthy is our priority. We’re working with our veterinarian and taking precautions to protect both.”

For more information, including BOAH’s response plan, visit www.in.gov/boah/species-information/cattle-sheep-and-other-ruminants/cattle-dairy-and-beef/h5n1influenzaincattle/.