USDA Requiring Avian Flu Testing in Some Dairy Cows

Apr 26, 2024

By HOPE KIRWAN 

Wisconsin officials continue to emphasize on-farm protections against avian flu ahead of a new federal mandate to test more dairy cattle for the virus.

The U.S. Department of Agriculture released a federal order on Wednesday that requires farms to test lactating dairy cows for highly-pathogenic avian influenza before moving them between states. The order also requires that labs report all positive tests to the federal agency.

During a call with reporters, Wisconsin State Veterinarian Darlene Konkle said Wisconsin already requires any positive tests for influenza virus found in livestock to be reported to the state Department of Agriculture, Trade and Consumer Protection.

She said cows moving across state lines are already required by state and federal rules to have a certificate indicating they’ve been examined by a veterinarian.

The newly-required tests will be handled by the Wisconsin Veterinary Diagnostic Laboratory or another federally approved lab, Konkle said, adding that USDA will cover the cost. For dairy producers looking to move cows, she said it will likely mean they need to allow more time for planning.

“Contact with their veterinarian is important, to set up testing and give time for negative results to be received,” she said. “We’re getting more information from our lab on what those turnaround times are expected to look like.”

Konkle said at this time, there are no additional requirements for moving cattle within the state.

Wisconsin has not had a confirmed case of avian flu in dairy cattle. The virus first affected livestock on farms in Kansas and Texas in late March. It’s now been confirmed in dairy cows on 33 farms in eight states.

In the federal order released Wednesday, the USDA said they found highly pathogenic avian influenza, or HPAI, in a lung tissue sample from an asymptomatic cow. Officials said the cow originated from an affected herd and was culled, but did not enter the food supply.

Amid questions around virus transmission, officials say biosecurity measures can reduce risk

Konkle said the new federal guidance only applies to lactating cows because they appear to be at highest risk of spreading the virus to other livestock.

“We know cattle do concentrate the virus in their mammary glands, so that’s where we’re looking at gathering the most information,” she said.

She said there has been an instance of suspected spread from a dairy herd to a poultry flock. The USDA confirmed in the federal order on Wednesday that eight poultry farms in five states, including Minnesota, have been infected with the same HPAI virus genotype that’s been detected in dairy cattle.

Federal officials have confirmed that the virus can spread from cow to cow, but said it’s unclear exactly how the virus is being spread. But they noted “the virus is shed in milk at high concentrations.”

“Anything that comes in contact with unpasteurized milk, spilled milk, etc. may spread the virus,” USDA officials said in a fact sheet released Wednesday. The fact sheet added that other sampling has indicated that respiratory transmission is not a primary means of spread.

Konkle said strong biosecurity measures continue to be the best way to protect dairy and poultry farms from the virus. Recommendations include minimizing access of wild birds to cattle and quarantining new animals for a minimum of 21 days.

“Certainly, it might look different from farm to farm,” she said. “There’s not necessarily a one-size-fits-all approach to biosecurity.” 

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