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USDA Issues Dairy Cow Testing Mandate
By Chris Clayton
Wednesday, April 24, 2024 1:29PM CDT

OMAHA (DTN) -- USDA will require testing of lactating dairy cows crossing state lines for the H5N1 virus after fragments of the virus were found in tests of commercial dairy products.


-- USDA is now going to require H5N1 testing for all lactating dairy cows moving across state lines.

-- USDA also will mandate that laboratories and state veterinarians report all positive influenza A tests in livestock to USDA's Animal and Plant Health Inspection Service (APHIS).

-- FDA is now doing much broader testing of dairy products nationally to determine the extent of H5N1 fragments in pasteurized dairy products.

-- FDA said H5N1 is neutralized by pasteurizing. They have been testing H5N1 in chicken eggs and the heat needed to destroy the virus in chicken eggs is lower than pasteurizing.

-- CDC says there is a low risk to human health and has seen no increase in foodborne illnesses.


USDA is issuing an order Thursday that will go into effect April 29 requiring dairy farmers sending lactating cows across state lines to have those cows tested for H5N1 before they can move. The testing at USDA labs would likely take one to three days, though USDA is looking to develop more rapid tests that can be used in the field, said Mike Watson, administrator for USDA's Animal and Plant Health Inspection Service.

Producers with cows that test positive will be required to provide epidemiological information on those cows, including animal movement tracing information, especially if they intend to move the cattle across state lines.

Cows that test positive would remain on their home farms and then be retested in 30 days before they could move across state lines, Watson said. He repeated that the virus is not fatal for cows, and they mostly recover quickly.

"We believe the current risk to the public is low and we continue to see infected cows recover after supportive care with little to no associated mortality," Watson said.

Watson and FDA officials indicated there have been situations where dairy farms have been reluctant to allow officials on their farms to test cattle. "That has been improving most recently," he said.

In another security measure, USDA's federal order will require labs and state veterinarians to report any positive influenza A cases in livestock to APHIS.

So far, USDA has reported 33 dairy herds in eight states have been confirmed as infected by USDA's National Veterinary Services Laboratories. The latest was another Idaho dairy on April 19.

Vilsack said the focus remains on lactating dairy cows because that is when cows are testing positive. Vilsack also said USDA will cover the costs of the tests.

The testing order does not apply to beef cattle and USDA so far has not found any positive H5N1 infections in beef cattle.

At least one dairy cow going to slaughter was asymptomatic, but USDA tested the cow's lung and it came back positive. The cow was condemned and did not enter the food supply.


In terms of spreading, USDA has noted spread between cows in the same herd, spread from cows to poultry and spread between herds, and now more testing has found asymptomatic cows that are positive without any signs of illness. Watson said there is likely spread due to mechanical transmission on farms such as from equipment in dairy parlors.

Agriculture Secretary Tom Vilsack said there have been at least eight instances in which a dairy farm has infected an adjacent poultry farm. USDA officials said that was validated because the sequence of the virus was identical on both the dairy farms and the poultry operations.

"This is a novel circumstance that's not been confronted before, that's why there's a premium in knowledge and information and testing," Vilsack said.


The tests showing fragments of the virus in commercial dairy products moved federal officials to open up Wednesday about what they know.

Officials held two separate press calls Wednesday. FDA and the Centers for Disease Control, along with USDA, held a call to talk about the safety of the milk supply and increased testing of dairy products. USDA then held a separate call to discuss the department's federal order on dairy cow testing and movement.

FDA reported Tuesday that samples of tested milk products had found genetic material of the H5N1 virus, but pasteurization had destroyed the effectiveness of the virus.

Don Prater, FDA acting director of Food Safety and Applied Nutrition, said the positive finding of the H5N1 virus in dairy products has prompted the FDA to conduct a nationwide testing program for dairy products.

"We take this current situation and the safety of the milk supply very seriously. FDA and USDA have indicated that based on information currently available, our commercial milk supply is safe because both of the pasteurization process and the diversion or destruction of milk from sick cows. This remains the case right now.

When asked about how destroyed fragments of the H5N1 virus got into commercial dairy products, Vilsack pointed out cows with symptoms of the virus produced milk that is discolored and thicker than normal milk and that milk is being destroyed. But cows that were asymptomatic did not show those signs.

"We do know there were asymptomatic cows -- cows that had the virus but didn't necessarily exhibit any sign that milk ... didn't necessarily give any indication that it had had virus," Vilsack said.

Vilsack added it's important to reiterate that the virus did not survive pasteurization.


The National Milk Producers Federation called USDA's testing actions "appropriate" due to the presence of virus in dairy herds and the focus on both human and animal health.

"Today's announcements and actions underscore that continued concern and focus on the well-being of animals and those who care for them," said Gregg Doud, president and CEO of NMPF.

Doud added that USDA, FDA and scientific research has established that the consumer milk supply is safe. Pasteurization renders the H5N1 virus, like other viruses, inactive, an important reminder to consumers of its value as a basic safeguard for human health. "We appreciate that these agencies are sharing this message, which will help alleviate any concerns consumers may have."

USDA's federal order: www.aphis.usda.gov/sites/default/files/dairy-federal-order.pdf

Also see, "FDA Finds Fragments of HPAI Virus in Pasteurized Milk Samples," https://www.dtnpf.com/…

Chris Clayton can be reached at Chris.Clayton@dtn.com

Follow him on social platform X @ChrisClaytonDTN

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