The U.S. Department of Agriculture (USDA) has introduced a new National Milk Testing Strategy (NMTS) to address the highly pathogenic avian influenza (HPAI) H5N1 outbreak in dairy cattle that began in March 2024. The comprehensive approach aims to systematically track and control the virus’s spread across the United States through a detailed, multi-stage monitoring process.
Agriculture Secretary Tom Vilsack announced a new Federal Order requiring nationwide collection and sharing of raw milk samples for testing. The strategy represents a coordinated effort to understand and mitigate the potential risks associated with the H5N1 virus in dairy herds across the country.
The strategy is built around a five-stage approach designed to provide a comprehensive and systematic method of tracking and controlling the virus. The first stage involves nationwide silo monitoring, where the USDA will immediately begin testing milk silos at dairy processing facilities. This initial step will help identify where the disease is present, monitor emerging trends, and assist states in pinpointing potentially affected herds.
Building upon the silo monitoring results, the second stage focuses on state-level herd assessment. The USDA will collaborate with individual states to implement bulk tank sampling programs. These programs are specifically designed to identify herds within each state that may be affected by the H5N1 virus, providing a more granular approach to detection and monitoring.
In states where H5N1 is detected, the third stage involves rapid detection and response. The Agricultural and Plant Health Inspection Service (APHIS) will work quickly to identify specific cases and implement comprehensive response measures. These include enhanced biosecurity protocols, utilizing existing USDA incentive programs, implementing movement controls, and conducting thorough contact tracing to prevent further spread.
The fourth stage is focused on demonstrating the ongoing absence of H5N1N1 in dairy cattle in unaffected states. Once all dairy herds in a state are considered free from the virus, APHIS will continue regular sampling of farm bulk tanks to ensure the disease does not re-emerge. The frequency of sampling will progressively decline as states consistently demonstrate negative test results, moving from weekly to monthly to quarterly testing.
The final stage aims to demonstrate freedom from H5N1N1 in the entire U.S. dairy cattle population. After all states have successfully progressed through the previous stages, APHIS will work to establish periodic sampling and testing that illustrates the long-term absence of the virus from the national herd.
The initial implementation of this strategy will include six states: California, Colorado, Michigan, Mississippi, Oregon, and Pennsylvania. However, USDA plans to ultimately involve all 48 contiguous states in this comprehensive testing program.
The new Federal Order introduces three critical requirements. First, it mandates the sharing of raw milk samples from dairy farms, milk transporters, and processing facilities upon request. Second, it requires herd owners with positive cattle to provide detailed epidemiological information to support contact tracing and disease surveillance. Third, it compels private laboratories and state veterinarians to report positive test results, ensuring a transparent and comprehensive tracking system.
This new order complements the previous April 24 Federal Order, which required mandatory testing of lactating dairy cows before interstate shipment. The strategy was developed through extensive collaboration, incorporating input from state, veterinary, and public health stakeholders.
Health and Human Services Secretary Xavier Becerra emphasized the collaborative nature of the effort, highlighting the primary goal of protecting public health and ensuring the safety of the food supply. The USDA will host information sessions for state animal health officials and dairy regulators on December 10 and 11 to explain the National Plant Silo Monitoring and sampling procedures in detail.
Since the first H5N1 detection in livestock in March 2024, the USDA has been proactively working to understand and control the virus. The agency has provided free H5N1N1 livestock testing through the NAHLN laboratory network, received samples from all 48 contiguous states, and uploaded whole genome sequences of detected viruses to public databases.
The agency has continued to stress the importance of biosecurity practices for farmers. Support programs are available to help cover costs related to biosecurity programming, personal protective equipment for employees, and veterinary care. Additionally, the USDA has conducted collaborative research with the FDA to test the safety of milk and dairy products, reaffirm pasteurization’s effectiveness, and demonstrate that properly cooking beef can inactivate the H5N1 virus.
While the strategy primarily focuses on dairy herds, its broader aim is to protect both animal and human health. The comprehensive testing approach is designed to quickly identify and contain potential virus spread, minimizing risks to farmworkers and the broader population.
In the coming weeks, USDA plans to expand the testing program, working closely with each state to develop milk testing plans that meet local needs while maintaining a consistent national approach. This National Milk Testing Strategy represents a significant, coordinated effort to address the H5N1 outbreak in U.S. dairy cattle, combining scientific research, systematic testing, and supportive resources for farmers.
Commenting on this article, one national food poisoning lawyer said, “This is another proactive step by the USDA to help protect the public’s health. When it comes to choosing pasteurized over raw milk, I recommend following government guidelines to drink pasteurized milk because it is both safe and full of nutritional value.”
