With over 950 cases of Highly Pathogenic Avian Influenza A (HPAI H5N1) detected in United States cattle across 17 states, according to the United States Department of Agriculture, the dairy industry is adapting and taking precautions to ensure consumers and their herds are protected.

While HPAI H5NI has not yet been detected in Wisconsin cattle, precautions have been taken including at the Pierce County Fair in August where no dairy cows were brought in and the poultry were judged and sent home before other animals could arrive.

According to Mayo Clinic, bird flu rarely affects humans, with the primary worry of health officials being a future mutation that can infect the population. What HPAI H5NI does affect is a variety of other animals.

The virus can be lethal to animals including chickens, turkeys and cats, with the effects on cattle still being debated by many. The American Veterinary Medical Association claims a 2% mortality rate among infected cattle, while others, including a dairy council in California, have estimated a 10-15% mortality rate.

HPAI H5N1 is detected in dairy cattle through milk testing.

“National Milk Testing Strategy (NMTS) facilitates comprehensive H5N1 (HPAI) surveillance of the nation’s milk supply and dairy herds,” Pierce County Veterinary Clinic Doctor of Veterinary Medicine Frank During stated. “It provides a strategy to identify which states and herds within them are affected with H5N1. The NMTS includes a combination of dairy processing plant silo monitoring and state-specific surveillance, ongoing testing for case investigation and response, and the mandatory testing for interstate movement of lactating dairy cattle.”

According to the USDA, as of Feb. 16, 42 states are enrolled in NMTS and performing active surveillance, but Wisconsin is not one of them. Not being enrolled in the strategy does not mean testing isn’t happening throughout the state, however.

The virus was first detected in March, and the USDA launched the NMTS in December, so states have been continually enrolling in recent months. There is a possibility more states could be added to the NMTS list as time goes on.

The USDA also put out a Federal Order in December, requiring additional testing and reporting for the virus for lactating dairy cows before interstate shipment.

Consumers are protected in the process, as the Food and Drug Administration found in a study that the pasteurization process is effective at killing the virus.

“The consumer of dairy products can rest assured that our food supply is safe and that all possible measures are taken to ensure this in the future. There is no need to panic,” During stated.

A storyline During said should continue to be monitored is similar to Mayo Clinic’s concern of the potential for mutations and variations.

“A new strain, the D1.1 strain of H5N1 avian influenza was detected in dairy cattle in Nevada in January 2025. This was the first time this strain had been found in dairy cattle,” During stated. “So it is conceivable that the virus is changing. This strain is found to be more virulent than the previous strain, but not much is known yet. It was incidentally discovered through routine bulk tank testing through NMTS.”

During said most cattle can recover after treatment, and if there is suspicion or detection within a herd, farmers should contact their herd veterinarian to take samples. In the instance of a positive test, the state veterinarian would likely step in to make “necessary restrictions.”

“Biosecurity for highly pathogenic avian influenza (HPAI) in cattle includes limiting contact with wild birds, managing animal movement, and keeping the farm clean,” During stated.

He listed oral, nasal and fecal secretions from waterfowl and other birds and secretions from cattle including raw milk as ways the disease is spread throughout cattle herds. Small mammals including cats, raccoons and skunks were another group cited by During that can be affected by the wild bird strain of H5N1. This group is considered by many to be a dead-end host because the virus can get inside the animal but cannot progress its life cycle further, according to During.

The situation is one that changes by the day with new test results, new findings and new regulations.