cows in barn

Highly pathogenic avian influenza (HPAI, H5N1), a highly contagious and deadly foreign animal disease of domestic and wild birds, has made the jump to dairy cows. Cows are among at least 48 mammal species recently affected by this virus. A single spillover event from wild birds to a herd of cattle in Texas is believed to have led to the current outbreak, which then spread to herds in other states. Testing and research at this time have shown no changes in the virus that would make it easy for humans to become infected, or for the virus to pass from human to human.

The USDA Animal and Plant Health Inspection Service has confirmed bovine influenza A in nine U.S. states as of May 2024 (Colorado, Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, South Dakota, Texas). No cases of bovine influenza have been identified in Vermont or in other New England states at this time.

A federal order (issued April 24, 2024), effective April 29, 2024, requires mandatory testing prior to interstate movement of some types of dairy cattle. Lactating dairy cows that will travel across state borders, unless going directly to slaughter, must receive a negative test result for the influenza A virus from a National Animal Health Network Laboratory (NAHLN), along with a certificate of veterinary inspection.

University of Vermont animal health specialists are keeping track of this disease outbreak, coordinating with agricultural industry stakeholders, and providing relevant, current and accurate resources to keep Vermonters informed.

Whether you are a dairy farmer, milk hauler, veterinarian, 4-H participant, or consumer (especially those who consume raw milk), check the list of resources here to stay current with the progress of this outbreak. Learn how to practice “biosecurity,” one of the best ways to prevent a disease infection in livestock, poultry, and potentially humans. Continual monitoring is being performed because the virus is zoonotic, meaning it has the ability to be passed between animals and humans. People having close contact with cows, especially people milking cows, are encouraged to wear personal protective equipment to minimize their exposure.

Dairy Producers and Milk Haulers

Farms should continue to monitor their dairy cows for signs of illness to ensure that milk from sick cows does not enter interstate commerce. Producers that identify illness in their cows should work with the State Veterinarian to submit samples for testing.

UVM Extension developed a fact sheet on HPAI in dairy cows: download "Highly Pathogenic Avian Influenza H5N1 in U.S. Dairy Herds" (PDF).

Disinfection - recommendations that kill the avian influenza A virus on farms:
a. Disinfection 101 (PDF): Cleaning and disinfection for animal settings. 
b. A searchable list of disinfectants effective against avian influenza: U.S. Environmental Protection Agency (EPA) registered antimicrobial products list.
c. Synthetic substances allowed for use in organic livestock production: The Code of Federal Regulations lists substances, including disinfectants and sanitizers.
d. Bleach dilution ratio chart for disinfecting

Farm worker safety and protection: U.S. Centers for Disease Control and Prevention (CDC) recommendations for worker protection and PPE to reduce exposure to influenza A viruses

Enhanced Biosecurity Planning / Secure Milk Supply Guidance:
a. Enhanced biosecurity training information
b. How to get a farm premises ID

Biosecurity signs can help protect your farm animals, workers, and visitors from bringing diseases to the farm or leaving with them on boots, clothing, etc. Download and print out biosecurity signs in English and Spanish.

USDA is offering financial assistance for producers with herds affected by H5N1: for employee PPE, biosecurity planning, safe milk disposal, veterinarian costs associated with a positive H5N1 confirmation, and more. Read USDA, HHS Announce New Actions to Reduce Impact and Spread of H5N1.

Youth in 4-H, FFA: Livestock and Poultry at Fairs and Exhibitions

Agricultural events, along with the growing, on-farm business of agritourism, are opportunities for animals and people to share and spread diseases, particularly zoonotic diseases (spread between animals and humans).

A series of biosecurity learning modules for youth in agriculture, and adaptable for post-secondary instruction: Youth biosecurity learning modules.

Vermont state veterinarian recommendations on how to safely exhibit animals at fairs, shows, and exhibitions:  Recommendations to safely exhibit animals.

The Defend the Flock program includes information for youth on how to protect poultry from diseases: Defend the Flock youth program.

How people can safely work and interact with farm animals: Protecting yourself while caring for and being around farm animals.

Consumers and Producers of Raw Milk

It is unknown at this time if the HPAI virus can be passed along to humans who consume unpasteurized (raw) milk. Raw milk has the potential to harbor disease-causing organisms and people should understand the risks.

The U.S. Food and Drug Administration (FDA) answered questions about raw milk and cheese concerns: Are there concerns about HPAI and raw milk?

An explanation of what raw milk is and links to more consumer materials about it: FDA information on raw milk.


The commercial milk supply is considered safe because of the pasteurization process that destroys potential disease-causing organisms in milk, and because milk is not being collected from sick cows.

FDA answers to questions about milk safety during the HPAI outbreak: FDA answers to milk supply safety.

The USDA Food Safety and Inspection Service is testing beef in states where dairy cows had tested positive for HPAI: Updates on beef safety studies during the HPAI outbreak.

During the agriculture fair season farm animal exhibitors and visitors should take precautions to protect animals and people from diseases: Livestock and poultry in public settings.


For questions or concerns, please contact the Vermont state veterinarian at or call 802-828-2421.