On Dec. 6, 2024, the U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) announced the start of its National Milk Testing Strategy (NMTS), which builds on measures taken by USDA and federal and state partners since the outbreak of highly pathogenic avian influenza (HPAI) H5N1 in dairy cattle was first detected in March 2024.

The USDA has issued a new Federal Order, as well as accompanying guidance, requiring that raw (unpasteurized) milk samples nationwide be collected and shared with USDA for testing. This new guidance from USDA, which was developed with significant input from state, veterinary and public health stakeholders, will facilitate comprehensive H5N1 surveillance of the nation’s milk supply and dairy herds.

USDA continues to stress to farmers nationwide that effective biosecurity practices are the best weapon against the spread of disease, and that all farms should review their current biosecurity measures and ensure best practices identified over the past eight months are incorporated, even if H5N1 has not been detected in their state or region.