Highly Pathogenic H5N1 Avian Influenza in Dairy Cattle

Highly Pathogenic H5N1 Avian Influenza has been confirmed by USDA on dairy farms in several U.S. states. NMPF continues to closely monitor the rapidly evolving animal health issue and is working with federal and state partners to share updates and guidance as it becomes available. NMPF members, associate members and sponsors are eligible to subscribe to alerts on this developing issue.

Nationwide Mandatory Testing for Interstate Dairy Cattle Movements

USDA on April 24 issued a federal order requiring pre-movement testing for the interstate movement of lactating dairy cattle. Starting Monday, April 29, a negative test result for highly pathogenic H5N1 avian influenza will be required for all interstate movement of lactating dairy cattle before a Certificate of Veterinary Inspection can be issued.

USDA also announced that all laboratories and state veterinarians will be required to report positive H5N1 cases to USDA, a move that aims to limit the risk of virus spread to protect dairy workers, dairy herds and poultry facilities. For affected farms, the Federal Order will require business owners with dairy cattle that test positive for interstate movement to complete a comprehensive epidemiological questionnaire and provide animal movement tracing.

USDA’s actions are intended to enable USDA to take necessary measures to contain the disease and provide essential data for surveillance and epidemiological research. Accurate and timely reporting is essential to understanding the prevalence, distribution and dynamics of the virus, and the information collected is crucial for developing effective prevention and control strategies.

States with Confirmed H5N1 Cases

  • Colorado: 4 cases
  • Idaho: 20 cases
  • Kansas: 4 cases
  • Michigan: 24 cases
  • New Mexico: 8 cases
  • North Carolina: 1 case
  • Ohio: 1 case
  • South Dakota: 5 cases
  • Texas: 18 cases
  • Wyoming: 1 case

Milk & Meat Safety

There continues to be no concern about the safety of the milk supply or that this circumstance poses a risk to consumer health because products are pasteurized before entering the market, per the Food and Drug Administration (FDA). Only milk from heathy animals is authorized for distribution into interstate commerce for human consumption. Additionally, pasteurization has continually proven to inactivate bacteria and viruses, including influenza, in milk.

USDA and FDA remind consumers that raw milk should not be consumed. Raw milk is a key vehicle in the transmission of human pathogens. As this situation continues to evolve, NMPF joins USDA, FDA and the International Dairy Foods Association in strongly recommending that all raw milk and raw milk components be heat-treated to a temperature and duration that kills harmful pathogenic bacteria and other microorganisms, including HPAI viruses, regardless of the product’s intended use for human or animal consumption. FDA also recommends out of an abundance of caution that milk from cows in an affected herd not be used to produce raw milk cheeses.

All dairy cattle are also subject to the Federal Meat Inspection Act and must be slaughtered and processed under inspection by USDA’s Food Safety and Inspection Service, ensuring that all meat entering the food supply has been inspected and approved for human consumption.


Protecting the Dairy Workforce

According to CDC’s interim recommendations, people should avoid unprotected exposures to sick or dead animals, as well as raw milk, manure or materials contaminated by animals with confirmed or suspected HPAI virus infection. When working with infected or potentially infected animals, farm employees should wear personal protective equipment (PPE) such as an N95 filtering facepiece respirator, eye protection and gloves, and perform thorough hand washing after contact with infected animals, carcasses, milk or manure.

Workers should receive training on and demonstrate an understanding of:

  • When to use PPE: When in direct or close contact (within about six feet) with sick or dead animals, as well as manure and milk from confirmed or suspected HPAI cases.
  • What PPE is necessary: PPE includes a properly fitted unvented or indirectly vented safety goggles, disposable gloves, boots or boot covers, a NIOSH-Approved particulate respirator, disposable fluid-resistant coveralls, and disposable head cover or hair cover.
  • How to properly put on, use, take off, dispose and maintain PPE; and
  • PPE limitations.

Persons working with or around cattle, even if not in close contact, should avoid eating, drinking, smoking, chewing gum and other such activities in potentially contaminated areas. They should also avoid rubbing or touching their eyes and should perform thorough handwashing regularly.

Anyone exposed to HPAI-infected cattle should be monitored for signs and symptoms of acute respiratory illness beginning after their first exposure and for 10 days after their last exposure. If any person develops acute respiratory illness symptoms during the monitoring period, the state health department should be notified and the sick person should be isolated.



Dairy producers with affected cows are reporting a rapid onset illness in herds, specifically among older, lactating cows. Signs include:

  • Decreased herd-level milk production
  • Acute, sudden drop in production
  • Decrease in feed consumption
  • Abnormally dry feces
  • Fever
  • Thicker, more concentrated, colostrum-like milk

For the dairies whose herds are showing signs, on average 10 percent of each affected herd appears to be affected, with no associated mortality reported among the animals. Infected dairy cattle are expected to fully recover within a few weeks.

Producers should continue to closely monitor their cattle for illness, including decline in milk production, and immediately separate sick animals.

If you observe clinical signs in your herd consistent with this outbreak, contact your veterinarian immediately. Veterinarians who observe these clinical signs and have ruled out other diagnoses on a client’s farm should contact the state veterinarian, follow USDA’s testing recommendations and submit a complete set of samples to a NAHLN laboratory. USDA will reimburse producers for initial testing of suspect animals.


Robust biosecurity protocols are critical to preventing and managing A5N1 on dairy farms. That includes limiting wild bird exposure, limiting traffic into and out of farm properties and limiting visits to employees and essential personnel.

USDA’s latest guidance urges particular attention to mammary health, including special attention to good milking practices, such as equipment disinfection and milking sick cattle separately or last prior to parlor cleaning.

The agency strongly recommends limiting animal movement as much as possible. If cattle must be moved, USDA recommends pre-movement testing of milk samples from lactating cows and nasal swabs for non-lactating cattle, by PCR for Influenza A and H5 virus, at a National Animal Health Laboratory Network (NAHLN) laboratory. New animals should be isolated for a minimum of 21 days before being integrated with the rest of the herd.

USDA also encourages limiting non-production animal access to farm areas and implementing measures to exclude domestic pets, including cats, and wildlife from buildings.

Avian influenza virus is easily killed by many disinfectants. Keeping equipment, clothing and footwear clean helps protect cattle health from many viruses and bacteria. See the EPA-registered list of disinfectants labeled to kill HPAI virus.


Biosecurity Resources

FARM Program Expectations

The National Dairy FARM Program requires FARM Evaluators to adhere to strict biosecurity procedures when conducting in-person evaluations. This includes parking vehicles in as clean of an area as possible, wearing clean clothes and disposable boots, and changing clothes between farms or wearing disposable coveralls when visiting multiple farms a day. FARM Evaluators should not visit farms with an active HPAI H5N1 outbreak. Please contact dairyfarm@nmpf.org with any questions.

Second Party Evaluations / Third Party Verifications

  • Evaluators and Verifiers should not visit farms with confirmed HPAI cases until cattle have recovered.
  • Let FARM know ASAP if a due dates need adjustments on a farm with on-going cases.

Biosecurity Expectations

  • Park vehicles in a clean area and away from animal areas or where animals may travel.
  • Wear clean clothes.
  • Only visit one farm a day if possible
  • Do not walk through areas where bird feces may be present before entering livestock areas.
  • Wear disposable boots and/or clean footwear with an EPA-registered disinfectant labeled for  Avian Influenza.
  • Wash hands after removing boots/boot covers.
  • Avoid being in the parlor or barn during milking.
  • Avoid going into the milk house if possible.