WASHINGTON, June 25, 2024 — Agriculture Secretary Tom Vilsack emphasized the importance of biosecurity in mitigating the spread of H5N1 among dairy cattle. "The more we learn about H5N1, the more we understand that good biosecurity is a critically important path to containing the virus," he stated.
This past winter, migrating wild birds infected with H5N1 transferred the virus to dairy cattle in the Texas panhandle region, marking the first reported case in dairy cattle. Subsequently, cows shipped from this area spread the disease across other parts of the country. Currently, H5N1 has been detected in 115 dairy herds across 12 states.
H5N1 is highly pathogenic in birds, causing severe illness and high mortality rates. The USDA has collaborated with poultry and egg producers for over a decade to manage this virus. Poultry farmers have adopted practices such as depopulating affected flocks and enhancing biosecurity measures to control its spread. Despite these efforts, migrating birds continue to pose a threat by bringing H5N1 with them.
In contrast, H5N1 affects cattle differently. Infected dairy cows experience a sudden drop in milk production and general malaise but typically recover after a few weeks without fatality. Consequently, the USDA has issued specific recommendations for dairy farmers on managing and testing for the disease in cattle. These guidelines were developed with input from various experts including dairy producers, veterinarians, state officials, and USDA researchers.
Data indicate that cow movements from the Texas panhandle initially facilitated H5N1's spread to other states. To address this issue, the USDA implemented a Federal Order mandating that all lactating cows be tested before interstate movement. This order aims to enhance testing practices among producers and provide valuable data for limiting disease impact and understanding its transmission.
Epidemiological analysis revealed that H5N1 concentrates in the udders of sick cows and their milk can contain high viral loads, facilitating easy transmission through even minimal contact. The virus likely spreads between dairies via normal business operations involving people’s clothing or shoes, vehicles, and equipment.
Improved biosecurity practices are essential to controlling H5N1's spread among animals and farm operations. Recommended measures include thorough cleaning and disinfecting of parlors, equipment, clothing, vehicles; isolating sick cows; wearing personal protective equipment; and restricting farm access.
To support producers, USDA offers financial assistance for enhanced biosecurity plans, free H5N1 testing for dairy cattle along with associated shipping costs, veterinary services, personal protective equipment, and more. For herds affected by H5N1-related milk production losses, USDA plans to introduce compensation through ELAP (Emergency Assistance for Livestock), which covers 90% of eligible losses by statute.
Additionally, USDA has launched a Voluntary H5N1 Dairy Herd Status program aimed at encouraging producers to help contain the disease while minimizing operational disruptions.
USDA continues collaborating closely with federal partners such as CDC and FDA to safeguard farmworkers' health and ensure food supply safety remains intact. While human health risks are currently low due to continued transmission among dairy cows raising concerns about potential mammal-to-mammal spread adaptations could heighten human risk over time.
Ongoing studies confirm America's food supply safety standards remain robust. Meanwhile, USDA scientists are working on developing an H5N1-specific vaccine for cattle as part of long-term eradication efforts—a process expected to take considerable time due to its complexity.
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