Highly Pathogenic Avian Influenza (H5N1) in Dairy Cattle

​​How to Report Diseases
Anyone (veterinarians, producers, animal owners, etc.) who suspects a reportable animal disease is required to report it to a Federal or State Animal Health Official. Please follow the instructions on this webpage.
To report sick or dead wildlife, please visit the Department of Natural Resources (DNR) website​, email DNRWildlifeSwitchboard@wisconsin.gov, or call (608) 267-0866.​

General Information

DATCP continues to work with state and federal partners on detections of highly pathogenic avian influenza (HPAI/H5N1) virus in dairy cattle. While not currently reported to be causing high mortality in dairy herds, as it does in poultry flocks, HPAI/H5N1 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.​ 

No cases of HPAI/H5N1 in livestock have been reported in Wisconsin. Information on poultry detections in Wisconsin: DATCP Home Highly Pathogenic Avian Influenza in Poultry.​

Testing

​Lactating dairy cattle must receive a negative test for Influenza A virus at an approved National Animal Health Laboratory Network (NAHLN) laboratory:

  • Prior to interstate movement (crossing state lines)
    • Including moving to markets or sale barns in Wisconsin from other states
  • Prior to attending fairs or exhibitions in Wisconsin
    • Including Wisconsin-origin cows

Milk samples must be collected no more than seven (7)​ days prior to movement. Testing is available to producers at no cost through USDA APHIS at NAHLN laboratories including the Wisconsin Veterinary Diagnostic Laboratory. Producers may also apply for reimbursement of shipping and veterinary fees for collection of samples through USDA APHIS Financial Assistance for HPAI in livestock.

Inter- and Intrastate Milk Testing

Since April 2024, there have been 7,585 raw milk samples tested for inter- and intrastate animal movement. Of those, there have been zero positives.​

National Milk Testing Strategy (NMTS)

On May 19, 2025, the Wisconsin Department of Agriculture, Trade and Consumer Protection announced that Wisconsin would soon begin testing as part of the USDA Animal and Plant Health Inspection Service (APHIS) National Milk Testing Strategy (NMTS). With the help from industry partners, Wisconsin is sampling milk at the farm level with the goal of testing each farm approximately every month.

This site will be updated weekly as the testing continues. DATCP expects to continue to be able to utilize samples that are already collected for routine milk testing to streamline the testing process.​​

Updated July 2, 2025, 1:00​ p.m.​​
Date Range​
# of Milk Samples Tested
​Samples with H5N1 Detected
​May 25-31, 2025
​656
​0
​June 1-7, 2025
​716
​0
​June 8-14, 2025
​756
​​0
​June 15-21, 2025
​1,060
​​0
​June 22-28​, 2025
​747
​0
Total
​3,935
​0


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. 

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:

What if HPAI/H5N1 is Detected in Wisconsin?

DATCP is committed to working with state and federal partners, veterinarians, and producers to prevent the spread of HPAI/H5N1 to Wisconsin dairies. Efforts continue to follow cases in other states, prepare for a detection in Wisconsin, and prevent further spread.

2024-25 HPAI Communications 






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