REDFIELD, Iowa (DTN) -- Due to the continuing spread of highly pathogenic avian influenza H5N1 in dairy cattle across the country since it was first detected in March 2024, USDA's Animal and Plant Health Inspection Service (APHIS) announced the start of its National Milk Testing Strategy (NMTS). Today's federal order requires raw milk samples nationwide be collected and shared with USDA for testing.

"Since the first HPAI detection in livestock, USDA has collaborated with our federal, state and industry partners to swiftly and diligently identify affected herds and respond accordingly. 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," said U.S. Secretary of Agriculture Tom Vilsack in a news release.

"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. USDA is grateful to our partners who have provided input to make this strategy effective and actionable, and we look forward to continued collaboration in seeing this through."

The original increase in testing and monitoring for H5N1 started at the end of October when USDA implemented a tiered strategy to collect milk samples to assess better where H5N1 is present. In April 2024, a federal order was put in place to require the testing of lactating cows before interstate movement. This order also requires all laboratories to report positive tests to the USDA. Some states have put additional testing requirements into place to help prevent the spread of the virus.

TESTING SYSTEM TO HELP FIND SOURCE

The NMTS is set up to increase the understanding of the virus' spread in the U.S. by using a structured, uniform and mandatory testing system to help identify which states and specific herds are infected with H5N1. It then supports the implementation of biosecurity measures to lower the risk of transmission to other livestock and protect farm workers to lower their risk of exposure.

As part of the NMTS, APHIS will work with each state to execute testing. Once the state begins testing, it will then be placed into one of five stages based on the HPAI H5N1 virus prevalence in the state. The ongoing testing can move states into different stages to help eliminate the virus.

In Stage 1, the USDA begins nationwide testing of milk silos at dairy processing facilities. This will help USDA to identify where the virus is present, monitor trends and help states identify potentially affected herds. Stage 2 builds on the results from Stage 1 by determining a state's H5N1 dairy cattle status and helping identify affected herds. Stage 3 is for the states with H5N1 detections, and helps implement rapid response measures, setting up enhanced biosecurity using USDA's existing incentives programs, movement controls and contact tracing. Stage 4 is for states unaffected by H5N1 due to no presence of the virus in milk samples. Testing will continue over time and if a state becomes affected, it will return to Stage 3. The goal is to reach Stage 5 when all U.S. dairy cattle are free of H5N1 once all states have cleared Stage 4 testing long-term.

"This testing strategy is a critical part of our ongoing efforts to protect the health and safety of individuals and communities nationwide," said Health and Human Services (HHS) Secretary Xavier Becerra. "Our primary responsibility at HHS is to protect public health and the safety of the food supply, and we continue to work closely with USDA and all stakeholders on continued testing for H5N1 in retail milk and dairy samples from across the country to ensure the safety of the commercial pasteurized milk supply. We will continue this work with USDA for as long and as far as necessary."

USDA continues to stress the importance of good biosecurity practices to combat the H5N1 virus in all livestock, poultry and humans. HPAI continues to spread throughout the poultry industry with flocks in California and Iowa being the most recently affected.

The first states brought into the program for testing will be California, Colorado, Michigan, Mississippi, Oregon and Pennsylvania. Since the outbreak began there have been 720 confirmed cases of H5N1 in dairy cattle in 15 states.

For more about USDA's response to HPAI in dairy cattle, visit www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/livestock.

Jennifer Carrico can be reached at jennifer.carrico@dtn.com

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