Highly Pathogenic Avian Influenza (HPAI) in Dairy Cattle

General Information

DATCP continues to work with state and federal partners on detections of highly pathogenic avian influenza (HPAI) virus in dairy cattle. While not currently reported to be causing high mortality in dairy herds, as it does in poultry flocks, HPAI has been associated with many symptoms including decreased milk production and reduced appetite. The U.S. Department of Agriculture (USDA) National Veterinary Services Laboratories has now confirmed HPAI H5N1 in dairy herds in several states. Access the USDA list of detections in domestic livestock.​ 

​​Human Health​

​The Centers for Disease Control (CDC) is reporting cases of people who have tested positive for HPAI H5N1 in the United States. According to the CDC, the human health risk assessment for the general public is low; however, people with close or prolonged, unprotected exposures to infected birds, livestock, other animals, or their environments are at greater risk of infection. 

• Access the interim recommendations from CDC​ for more information on prevention, monitoring, and public health investigations. ​

Biosecurity

DATCP encourages producers to practice good biosecurity including minimizing animal movements and isolating new additions to the herd. Current import rules can be found on the DATCP Cattle and Bison Movement webpage. It is important to check requirements prior to importing animals from any state, as requirements can change. Requirements such as official identification and certificates of veterinary inspection (CVIs) help ensure cattle entering Wisconsin are healthy prior to import.

Livestock events and exhibitions increase the risk of disease transmission, including further spread of HPAI/H5N1. Visit DATCP's Biosecurity Resources for Events webpage.​

Federal & State Orders 

Since March 2024, two Federal Orders and one State Order affecting lactating dairy cows are in effect:

• April 24, 2024 Federal Order – Testing prior to Interstate Movement
• DATCP Movement Guidance:
• Summary of Additional Requirements for Movement of Lactating Dairy Cattle
• DATCP Owner Hauler Statement for Lactating Dairy Cow Transport to Slaughter
• Federal Order Guidance:
• APHIS Requirements and Recommendations for HPAI/H5N1
• Testing Guidance for Influenza A in Livestock
• Limiting the Spread FAQ
• June 19, 2024 State Order – Movement to Fairs & Exhibitions
• DAH State Order FAQ
• This intrastate order requiring a negative Influenza A test prior to travelling to a show or exhibition will remain in effect until 60 days after the last detection of H5N1 in cattle herds in the United States.  
• December 6, 2024 Federal Order – National Milk Testing Strategy (NMTS)
• Wisconsin is participating in the NMTS.
• More information, including state status, is located: National Milk Testing Strategy | Animal and Plant Health Inspection Service
  
• National Milk Testing Strategy Pre-Approval Letter
  
• National Milk Testing Strategy Cooperative Agreement​
  

What Happens When HPAI/H5N1 is Detected in Wisconsin?

DATCP is committed to working with state and federal partners, veterinarians, and producers to prevent the further spread of HPAI/H5N1 to Wisconsin dairies. Efforts continue to follow cases in other states, test Wisconsin dairy farms through the National Milk Testing Strategy, and prevent further spread of the virus​.

• H5N1 Protocol: What To Do if H5N1 Is Confirmed on Your Dairy Farm
  

2026​ HPAI Communications ​

• April 1, 2026: National Milk Testing Strategy N​umbers Update​
  
• ​March 25, 2026: ​Update on National Milk Testing Strategy and HPAI in Wisconsin​
• March 18, 2026: Highly Pathogenic Avian Influenza Update
• March 11, 2026: Update on National Milk Testing Strategy Numbers​​​​​
• March 6, 2026: HPAI​ Detected in Walworth County and Jefferson County Poultry Flocks
• March 4, 2026: H5N1 Update from DATCP​
• March 2, 2026: HPAI D​etected in Dane County Poultry Flock
• February 27, 2026: HPAI Detected in Jefferson County Poultry Flock
• February 25, 2026: National Milk Testing Strategy Numbers Update
• February 18, 2026: Update from DATCP on the National Milk Testing Strategy
• ​February 11, 2026: National Milk Testing Strategy Update​
• February 4, 2026: Update on H5N1 Testing in Wisconsin​​
• January 28, 2026: Update on National Milk Testing Strategy Numbers​​​​​
• January 21, 2026: H5N1 Update from DATCP
• January 14, 2026: National Milk Testing Strategy Numbers Update​
• January 7, 2026: Update on National Milk Testing Strategy Numbers​​​