Wisconsin is set to implement monthly, mandatory milk sample testing across all dairy farms as part of the National Milk Testing Strategy (NMTS) to monitor for highly pathogenic avian influenza (H5N1) in cattle. This marks a shift from earlier protocols that collected samples at processing facilities, allowing testing to be done more efficiently at the farm level.
The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP), in coordination with the Wisconsin Veterinary Diagnostic Laboratory (WVDL) and the U.S. Department of Agriculture (USDA), will begin collecting one milk sample per dairy farm each month. These samples will be processed at WVDL, with the goal of enhancing disease surveillance while minimizing on-farm disruption.
Milk haulers will collect the samples during routine pickups, streamlining the process by using existing sample submissions sent to quality assurance labs. This approach addresses biosecurity concerns by avoiding the need for new personnel to visit farms.
If a milk sample tests positive for H5N1, DATCP’s Division of Animal Health will notify the farm and coordinate quarantine procedures. Farms may continue shipping milk if it meets standard quality guidelines—meaning the milk must not be discolored, stringy, or otherwise abnormal.
To date, Wisconsin has tested more than 6,000 milk samples with no confirmed cases of H5N1. Nationally, the USDA has reported over 1,000 confirmed cases of H5N1 in dairy herds across 17 states since March 2024, with the highest numbers found in California, Idaho, and Colorado.
Health officials continue to assure the public that commercially sold milk remains safe to drink. All retail milk in the U.S. must be pasteurized—a process that destroys the H5N1 virus and other pathogens. The risk to the general public remains low, and ongoing monitoring efforts help ensure continued safety in the food supply.
This expanded testing initiative comes amid broader concerns about food safety oversight. Although reports have surfaced about potential cutbacks within the U.S. Food and Drug Administration’s (FDA) dairy testing programs, FDA officials maintain that the agency is realigning responsibilities to state and local levels rather than reducing safety measures outright.
With over 5,300 dairy farms and more than 200 processing plants, Wisconsin’s proactive testing strategy underscores its leadership in national dairy safety and its commitment to supporting both producers and public health.
