Bird flu has infected a Benton County dairy herd this week, marking the first confirmed case of the virus in Minnesota cows.

But, as State Veterinarian Brian Hoefs said, "it was only a matter of time."

"It's important for dairy farmers to follow the example of this herd and test sick cows," Hoefs said in a Thursday statement. "The more the animal health community can learn about this virus today through testing and research, the better we can equip ourselves to prevent infections tomorrow."

Several dozen cows are sick. Farmers will destroy milk from the animals, and the cows will quarantine for 30 days, according to the Minnesota Board of Animal Health.

The board said public risk from avian influenza is currently low, though "people who work with or have direct contact with infected animals could be at risk of getting sick."

A dairy worker in Texas contracted bird flu this past March and recovered as avian influenza spread among cattle in several states. Two months later, a Michigan dairy worker tested positive with mild eye symptoms. Only one other person in the U.S., a poultry worker in Colorado, is known to have caught the virus during the current outbreak that began two years ago.

"Symptoms of avian influenza in people may include cough, sore throat, fever, red/watery eyes or discharge from the eyes," according to the board.

The U.S. Food and Drug Administration said this spring it found inactive traces of the virus in the milk supply, but health officials said pasteurized dairy remains safe.

"There continues to be no concern that this circumstance poses a risk to consumer health, or that it affects the safety of the interstate commercial milk supply because products are pasteurized before entering the market," the FDA said.

At a dairy farm east of Rochester on Thursday afternoon, Lt. Gov. Peggy Flanagan touted the opening of National Dairy Month by snacking on an ice cream cone and attesting to the safety of dairy products.

"Our job is to make sure that we're telling Minnesotans that milk is safe to drink," said Flanagan, who called dairy farming an "important part of our way of life here" as workers behind her tended to cows on a rotating milking parlor.

Shelly DePestel, vice president of the Minnesota Milk Producers Association and a dairy farmer outside Lewiston, said federal and state officials have assured producers that cows recover from bird flu infections.

"But it still gives us a little anxiety about what this could roll into," DePestel said

The cow cases come amid a resurgence in bird flu infections at Minnesota poultry operations, including the euthanization of tens of thousands of turkeys and more than 1.3 million egg-laying hens last month. That pushed the state's virus-related poultry losses to nearly 8 million since 2022.

State officials are urging dairy farmers to contact their veterinarian if cows appear sick. Symptoms include fever, lower milk production, loss of appetite and changes in manure consistency, the board said.