With 100 million dead birds, the poultry industry could serve as an example for dairy farmers to combat bird flu

DES MOINES, Iowa — As the U.S. dairy industry faces an outbreak of bird flu, with cases reported on dozens of farms and the disease spreading to humans, the egg industry may serve as an example of how to slow the disease. But it also shows how difficult the virus can be to eradicate.

There have been previous bird flu outbreaks in the U.S., but the current outbreak began in February 2022 and has led to the slaughter of nearly 100 million chickens and turkeys. While hotspots still exist, their frequency has declined in part due to biosecurity measures on farms and a coordinated approach between companies and agricultural authorities, experts say.

Dairy farmers could try to implement similar safety precautions, but the enormous differences between animals and industries limit the lessons that can be learned and applied.

How can a 700 kilogram cow and a 2.3 kilogram chicken suffer from the same disease?

The name bird flu is commonly used because the disease is mainly transmitted by wild birds, which can survive infection. Many mammals have also become ill, including sea lions and skunks.

Animals can become infected by eating an infected bird or by exposing themselves to an environment where the virus is present. However, there are big differences between cows and chickens in how they behave after infection.

Avian flu usually kills chickens and turkeys within a few days of infection, leading to immediate mass killings of birds. This is not the case with cows.

In several states, dairies have had to kill infected animals because symptoms persisted and their milk production did not recover. But that is not the norm, says Russ Daly, a veterinarian at South Dakota State University.

He said it appears that bird flu is not generally fatal to cows, but infected animals are more susceptible to other diseases typically found in dairy farms, such as bacterial pneumonia and udder infections.

What has the egg industry done to protect chickens?

Egg sellers have become cleanliness fanatics.

To prevent the spread of disease, egg producers require their workers to shower and change into clean clothes before entering the barn and to shower again after leaving. They also regularly wash trucks and spray tires with solutions to kill any residual virus.

Many egg production farms even use lasers and erect special fences to prevent wild birds from visiting.

“The era of scarecrows is over,” said Emily Metz, president of the American Egg Board.

Without those efforts, the current outbreak would be much worse, said Jada Thompson, a professor of agricultural sciences at the University of Arkansas. Still, it’s difficult to maintain that vigilance even when the cost of introducing a disease to a farm is so high, she said.

Broiler chickens have also been infected with bird flu, but such cases are rarer. One reason for this is that broiler chickens are killed at the age of 6 to 8 weeks and therefore have less time to become infected.

Can the same be done to protect cows and dairy workers?

Yes and no.

Dairies can certainly limit the spread of disease by restricting access to barns so that people and equipment don’t bring the virus in from elsewhere. Workers could also wear eye protection, aprons and gloves to protect themselves, but there’s no getting around it: Big animals make a lot of mess.

“The milking parlor is a warm, humid place where there is a lot of liquid splashing around, whether it’s urine, feces or water, because the cows are spraying milk everywhere. Cows might start a milking machine and cause the milk to splash,” said Keith Poulsen, director of the Wisconsin Veterinary Laboratory.

Additionally, dairies do not have the time or staff to disinfect milking equipment between animals, which could result in equipment becoming contaminated. Pasteurization kills bacteria and viruses in milk, making it safe for human consumption.

Poulsen said the dairy industry could follow the example of the poultry and pork industries and establish more formalized and better funded research facilities to respond more quickly to problems like bird flu – or prevent them altogether.

The dairy industry can also contain the spread of the disease by limiting the transport of dairy cows between states, Poulsen said.

Are there new efforts to combat the virus?

The U.S. Department of Agriculture will soon begin testing a vaccine that could be given to calves, offering protection to the animals while reducing the risk of illness among workers.

The egg industry also hopes researchers can develop vaccines for poultry that are quick, inexpensive and effective. Workers can’t give shots to the millions of chickens that may need vaccination, but industry officials hope a vaccine could be administered through the birds’ drinking water, through the pellets they eat or even before the birds hatch from their eggs.

Efforts to develop vaccines have become even more important now that the disease has spread to dairy cows and even some people, Thompson said.

“Part of what is being developed now is how we can vaccinate them in a way that is cost-effective and disease-resistant,” Thompson said.