WASHINGTON, D.C. – The USDA’s Animal and Plant Health Inspection Service (APHIS) recently ordered nationwide testing of raw (unpasteurized) milk from U.S. dairy farms and processors to test for highly pathogenic avian influenza (HPAI) to better monitor the virus’ spread in dairy cows. The testing was expected to begin Dec. 16.

The USDA’s Dec. 6 announcement comes on the heels of the start of its National Milk Testing Strategy, which builds on measures taken by the USDA and federal and state partners since the outbreak of the deadly bird flu in dairy cattle was first detected in March 2024.

As of Dec. 12, 832 cases of HPAI had been confirmed in 16 states, including Iowa, Michigan and Ohio, APHIS said. California had the most, with 617. Officials in North Carolina, Michigan, Idaho, and Ohio have connected infections in their states to dairy cows brought in from Texas.

The USDA said it is issuing this new federal order, requiring that raw (unpasteurized) milk samples nationwide be collected and shared with the USDA for testing, starting in six states: California, Colorado, Michigan, Mississippi, Oregon and Pennsylvania.

“Since the first HPAI detection in livestock, the USDA has collaborated with our federal, state and industry partners to swiftly and diligently identify affected herds and respond accordingly,” said USDA Secretary Tom Vilsack. “This new milk testing strategy will build on those steps to date, and will provide a roadmap for states to protect the health of their dairy herds.

“Among many outcomes, this will give farmers and farmworkers better confidence in the safety of their animals and ability to protect themselves, and it will put us on a path to quickly controlling and stopping the virus’ spread nationwide,” he added.

The USDA said this National Milk Testing Strategy is designed to increase the agency’s and public health partners’ understanding of the virus’ spread in the United States through a structured, uniform, and mandatory testing system that will help swiftly identify which states, and specific herds within them, are affected with HPAI.

Moreover, the USDA said the strategy will support the rapid use of enhanced biosecurity measures to decrease the risk of transmission to other livestock; and more importantly, inform critical efforts to protect farmworkers to help lower their risk of exposure.

The USDA said this latest federal order makes three new requirements: First, it requires the sharing of raw milk samples, upon request, from any entity responsible for a dairy farm, bulk milk transporter, bulk milk transfer station, or dairy processing facility that sends or holds milk intended for pasteurization.

Second, the order requires dairy herd owners with positive cattle to provide epidemiological (the study of how diseases affect populations and how to prevent and control them) information that enables activities such as contact tracing and disease surveillance.

Third, like the USDA’s initial April 24 federal order (which still requires the mandatory testing of lactating dairy cows prior to interstate shipment, and requires that all privately owned laboratories and state veterinarians report positive test results connected with those tests), this newly issued federal order requires that private laboratories and state veterinarians report positive results to the USDA that come from tests done on raw milk samples drawn as part of the strategy.

As part of the National Milk Testing Strategy, the USDA said it will work with each state to execute testing in a way that works for the state and that aligns with the strategy standards.

Once a state begins testing under the strategy, the USDA said it will place that state into one of five stages, based on the HPAI virus prevalence in that state. As states move to another stage, the agency will have a stronger picture of the progress toward eliminating HPAI at state, regional and national levels. The five stages are:

Stage 1: The USDA will immediately begin nationwide testing of milk silos at dairy processing facilities. This national sample will allow the USDA to identify where the disease is present, monitor trends, and help states identify potentially affected dairy herds, the agency said.

Stage 2: Building on the results of milk silo monitoring, in collaboration with states, the USDA said it will also stand up bulk tank sampling programs that will enable the agency to identify dairy herds in the state that are infected with HPAI.

Stage 3: For states with HPAI detections, the USDA said it will work quickly to identify specific cases and implement rapid response measures, including enhanced biosecurity using the USDA’s existing incentives programs, movement controls, and contact tracing.

Stage 4: Once all dairy herds in a given state are considered to be unaffected, the USDA said it will continue regular sampling of farms’ bulk tanks to ensure the disease does not re-emerge. Bulk tank sampling frequency will gradually decline as the state demonstrates continual silo negativity (e.g., weekly, monthly, and quarterly, if continually negative). If a state becomes affected, the USDA said it will re-engage detection and response activities, and the state will return to Stage 3.

Stage 5: After all states move through Stage 4, the USDA said it will work with the states to begin periodic sampling and testing to illustrate long-term absence of the virus from the national herd.

Michigan is one of the first six states to be tested for HPAI in dairy cattle, the USDA said.

Tim Boring, Michigan Department of Agriculture and Rural Development director, told Farm World, “As part of the USDA’s National Milk Testing Strategy to achieve national disease elimination status from HPAI, the Michigan Department of Agriculture and Rural Development has worked in concert with dairy cooperatives and industry partners to develop a testing approach utilizing milk samples collected for routine quality and regulatory requirements.

“Monthly samples from all licensed dairy herds in Michigan will be sent from labs to Michigan State University’s Veterinary Diagnostic Lab to be screened for HPAI, with non-negative results going to the USDA’s National Veterinary Services Laboratory for confirmation testing,” he said.

Michael Claffey, Illinois Department of Public Health public information officer, told Farm World, at this time, there is no start date for dairy cattle testing in Illinois.

“Illinois Department of Agriculture veterinarians and Illinois Department of Public Health dairy program staff will be meeting with USDA officials in the coming days (as of Dec. 11) to develop a dairy testing plan, and will be sharing information with stakeholders before the process gets underway,” he said.

For more information, visit: www.aphis.usda.gov