Joint Dairy Organization Statement on Highly Pathogenic Avian Influenza in Cows

  • 4 min read March 25, 2024


Caroline Krajewski

March 25, 2024—Earlier today, the U.S. Department of Agriculture confirmed highly 
pathogenic avian influenza (HPAI) in two dairy cattle herds in Texas and two herds in 

Importantly, USDA confirmed that there is no threat to human health and milk and dairy 
products remain safe to consume. Pasteurization (high heat treatment) kills harmful 
microbes and pathogens in milk, including the influenza virus. 

Also, routine testing and well-established protocols for U.S. dairy will continue to ensure 
that only safe milk enters the food supply. In keeping with the federal Grade “A” 
Pasteurized Milk Ordinance (PMO), milk from sick cows must be collected separately 
and is not allowed to enter the food supply chain. This means affected dairy cows are 
segregated, as is normal practice with any animal health concern, and their milk does 
not enter the food supply. 

Consumers in the United States and around the world can remain confident in the 
safety and quality of U.S. dairy.

Enhanced Biosecurity Protocols Underway on U.S. Dairy Farms

As information related to an illness affecting dairy cows in several states began to 
circulate over the past two weeks, USDA’s Animal and Plant Health Inspection Service 
(APHIS) worked with state veterinary authorities as well as federal partners including 
the FDA to swiftly identify and respond to detections and mitigate the virus’ impact on 
U.S. dairy production. Dairy farmers also have begun implementing enhanced
biosecurity protocols on their farms, limiting the amount of traffic into and out of their 
properties and restricting visits to employees and essential personnel. Avian influenza is 
an animal health issue, not a human health concern. Importantly, mammals including 
cows do not spread avian influenza—it requires birds as the vector of transmission and 
it’s extremely rare for the virus to affect humans because most people will never have 
direct and prolonged contact with an infected bird, especially on a dairy farm. As a 
precaution, dairy farmers are taking important measures to protect their workers.

The National Dairy FARM Program (NDFP) offers several valuable biosecurity 
providing dairy farmers with tools to keep their cattle and dairy businesses 
safe, including:

Everyday Biosecurity Reference Manual
Enhanced Biosecurity Prep Guide
Herd Health Plan Protocol Template – Biosecurity
Animal Movement Log
People Entry Log

Biosecurity practices guidance is available here.

Dairy farmers who observe clinical signs in their herd consistent with this outbreak, such 
as a significant loss of animal appetite and rumination or an acute drop in milk 
production, should immediately contact their veterinarian. Veterinarians who observe 
these clinical signs and have ruled out other diagnoses on a client’s farm should contact 
the state veterinarian and plan to submit a complete set of samples to be tested at a 
diagnostic laboratory.

What is Pasteurization? 

Pasteurization is a process that kills harmful bacteria and pathogens, including viruses,
by heating milk to a specific temperature for a set period of time. The processing of milk 
products involves pasteurization of the raw milk to a minimum of 161.5˚F for 15 seconds 
and then immediately cooling it. Ultra pasteurization is a process that heats milk at a 
higher temperature for specified times to extend a product’s shelf life.

What is Avian Influenza? 

Detections of avian influenza in birds, including chickens, are common in the United 
States in the spring and fall due to wild birds spreading the virus as they migrate to and 
from their seasonal homes. While it is uncommon for Highly Pathogenic Avian Influenza 
to affect dairy cows, USDA APHIS has been tracking detections of HPAI in mammals for 
many years in the United States, leading dairy farmers and veterinarians in the United 
States to prepare for this eventuality. As a result, dairy farmers have taken immediate 
measures to enhance biosecurity measures in and around dairy farms to keep the food 
supply safe.

About the Illness in Cows

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

  • Decreased herd level milk production
  • Acute sudden drop in production 
  • Decrease in feed consumption 
  • Abnormal feces and some fever
  • Older cows may be more likely to be severely impacted than younger cows 

According to dairy farmers and veterinarians reporting on affected herds, most affected 
cows recover within two to three weeks. 

Information for Affected Producers 

Producers who believe dairy cattle within their herd are showing the clinical signs 
described above should report these signs immediately to state veterinarians. Animals 
may also be reported to APHIS' toll-free number at 1-866-536-7593. 

Trade and Exports

The U.S. dairy industry will continue to work with the U.S. federal government, trading 
partners and the World Organization for Animal Health (WOAH) to encourage 
adherence to WOAH standards and minimize all unnecessary or unfair trade impacts. It 
is essential that trading partners do not impose bans or restrictions on the international 
trade of dairy commodities in response to these and future notifications and rely on the 
science-based food safety steps taken in U.S. dairy processing, namely pasteurization, 
in preserving market access. 

Additional Information

  • To provide context on the overall size of the U.S. dairy herd, there are more 9.3 million dairy cows in the United States. 
  • U.S. dairy export value was $8.11 billion in 2023, the second largest value on record