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Good Biosecurity is Key to Mitigating the Spread of H5N1

by Wyoming Livestock Roundup

By Tom Vilsack

The more we learn about highly pathogenic avian influenza (HPAI) A (H5N1), the more we understand good biosecurity is a critically important path to containing the virus. Containing and eliminating the virus in our dairy cattle is essential to protect the health of our herds and flocks, farmers, farmworkers, families and the rural economy they make possible.

This past winter, a group of migrating wild birds infected with H5N1 transferred the virus to dairy cattle somewhere in the Texas Panhandle region. This was the first reported case in dairy cattle. 

Cows shipped from the Panhandle spread the disease to other parts of the country, and now H5N1 – the same strain of HPAI found in wild birds and poultry flocks – has been found in 115 dairy herds in 12 states.

H5N1 in birds

H5N1 is highly pathogenic in birds, meaning birds that get the virus get very sick very quickly and almost always die as a result. This virus has been at the top of the list for risk of global pandemics for years, as it has circulated among birds and other species. 

The U.S. Department of Agriculture (USDA) has been working with poultry and egg producers for a decade to manage the virus, and it is a disease scientists understand well. 

For poultry farmers, depopulating affected flocks, disinfecting poultry houses, barns and equipment and improving biosecurity practices has helped control the spread of the disease while keeping people safe. 

Sadly, migrating birds bring H5N1 with them, so there will likely always be a threat of the disease for poultry farmers.

H5N1 in cattle 

H5N1 behaves very differently in cattle. Dairy cows with H5N1 often have a sudden drop in milk production, go off of feed and generally do not feel well. 

But unlike birds, sick cows do not typically die from the virus and generally recover after a few weeks, returning to full milk production. 

Thus, USDA is making different recommendations to dairy farmers to help them test for and manage the disease in dairy cattle. 

These recommendations were designed with input from experts, including dairy producers, veterinarians, state officials and USDA researchers.

Data shows the movement of cows shipped from the Texas Panhandle were initially responsible for the spread of H5N1 to different states, so USDA put in place a federal order – a type of temporary requirement – which directs all dairy farmers to test their lactating cows before moving them across state lines. 

The federal order has led to more producers testing their cows, most specifically for pre-movement to raise assurances, which has the added benefit of providing information so producers and veterinarians can take quick action to limit the impact of the disease and help us better understand its spread. 

As producers do more testing, USDA expects to continue to detect additional dairy herds infected with the virus. This is what USDA expected and is an indication the system is working as designed.


As producers, USDA scientists and veterinarians looked carefully at H5N1, including through detailed epidemiological analysis, we learned the H5N1 virus concentrates in the udder of sick cows and in cows’ milk, which can contain high loads of the virus. 

This means even just a small splash of milk can spread the disease. We also came to understand the disease likely spread between dairies in a community through normal business operations such as the movement of people – unintentionally on items like clothing or shoes – vehicles and equipment coming and going on a farm.

These findings indicate improved biosecurity is the key to limiting the spread of H5N1 to keep animals, workers and farm operations safe. 

Biosecurity is a set of practices which can help to limit or prevent the spread of virus or disease among animals, as well as people, plants and more. 

In this instance, enhanced biosecurity can include practices such as thoroughly cleaning and disinfecting parlors, equipment, clothing and vehicles; separating sick cows and limiting movement of cattle; wearing and disinfecting personal protective equipment and limiting traffic onto the farm.

USDA support

USDA has many options available to support producers, including the ability to help producers pay for enhanced biosecurity plans, free H5N1 testing for dairy cattle, free shipping to send test samples to the lab, free veterinary costs, free personal protective equipment and more. 

Moreover, for producers with H5N1 in their herd, USDA intends to introduce a program through the Emergency Assistance for Livestock, Honeybees and Farm-Raised Fish Program (ELAP), which is being developed to compensate eligible producers with positive herds who experience loss of milk production. 

By statute, ELAP is authorized to pay eligible producers 90 percent of the value of losses. The program would pay an amount per cow for a set period of time. 

Additionally, for producers who want to help contain the disease and reduce the burden on their operations, USDA recently announced a Voluntary H5N1 Dairy Herd Status program.

At the same time, USDA continues to work closely with federal partners at the Centers for Disease Control and Food and Drug Administration in the interest of protecting the health of farmworkers and farmers and reaffirming the safety of the food supply. 

USDA is taking animal health and human health concerns seriously through a whole-of-government response.

While the risk to human health remains low, USDA knows continued transmission among dairy cows can increase concerns the virus may adapt to be more susceptible via mammal-to-mammal spread and increase the risk for humans. 

Studies have confirmed our food safety system is working well and America’s food supply remains among the safest in the world. 

USDA scientists are also working with partners to develop a cattle-specific H5N1 vaccine, an important tool to eventually help eliminate the virus from the nation’s dairy cattle herd, but this process requires many steps and will take time.

The most important step individuals can take today is biosecurity. 

I am calling on producers to use our resources to enhance their biosecurity measures and states and producers to opt in to our support programs and herd monitoring programs, which are designed to limit the spread of this disease in dairy cattle.

Producers are going to lead the charge, but they won’t need to do it alone. USDA is here to support them every day, and we will continue to do all we can to protect animal and human health. 

I am confident with the right tools and the hardworking spirit of America’s farmers and farmworkers, together we can get it done.

Tom Vilsack is the 32nd U.S. Secretary of Agriculture and can be reached by visiting

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