DES MOINES, Iowa — Now the US dairy industry is facing a… bird flu outbreakwith cases reported in dozens of farms and the disease spread to peoplethe egg industry could serve as an example of how to slow the disease, but also shows how difficult it can be to eradicate the disease the virus.
There have been previous outbreaks of bird flu in the US, but the current one started in February 2022 and it has enforced the slaughter of almost 100 million chickens and turkeys. Hotspots still occur, but their frequency has decreased in part due to biosecurity efforts on farms and a coordinated approach between companies and agricultural officials, experts say.
Dairy farmers could try to implement similar safeguards, but the vast differences between animals and industries limit the lessons that can be learned and applied.
It is commonly called bird flu because the disease is largely spread by wild birds that can survive infections. Many mammals have also contracted the disease, including sea lions and skunks.
Animals can become infected by eating an infected bird or by exposure to environments where the virus is present. That said, there are big differences in how cows and chickens fared after becoming infected.
Bird flu typically kills chickens and turkeys within days of infection, leading to immediate mass killing of birds. This does not apply to cows.
Dairies in several states have reported having to kill infected animals because symptoms persisted and their milk production did not recover, but that is not the norm, said Russ Daly, a veterinarian at South Dakota State University.
He said it appears that bird flu is not usually fatal to cows, but an infected animal may be more vulnerable to other conditions commonly found in dairies, such as bacterial pneumonia and udder infections.
Egg operators have become clean freaks.
To prevent diseases from spreading, egg producers require workers to shower and put on clean clothes before entering the barn, and shower again when they leave. They also regularly wash trucks and spray tires with solutions to kill virus residue.
Many egg operations even use lasers and install special fences to discourage wild birds from stopping by for a visit.
“Gone is the day of the scarecrow,” said Emily Metz, president of the American Egg Board.
Without these effortsAccording to Jada Thompson, professor of agronomy at the University of Arkansas, the current outbreak would be much worse. Still, it's difficult to maintain such vigilance even when the costs of allowing illness into surgery are so high, she said.
Chickens raised for meat, known as broilers, have also been infected with bird flu, but such cases are less common. In part, that's because broiler chickens are killed when they are only six to eight weeks old, giving them less time to become infected.
Yes and no.
Dairies can certainly reduce the spread of disease by restricting access to stables so that people and equipment don't bring in the virus from elsewhere. Workers could also wear eye protection, aprons and gloves to protect themselves, but there's no way around it: big animals are messy.
“The parlor is a warm, moist place with a lot of liquid flying around, whether it's urine, feces or water, because they squirt from the areas. Cows can trigger a milking machine to create splashes of milk,” said Keith Poulsen, director of the Wisconsin Veterinary Laboratory.
Dairies also don't have the time or staff to disinfect milking equipment between animals, which can cause the equipment to become contaminated. Pasteurization kills bacteria and viruses in milk, making it safe for people to drink.
Poulsen said the dairy industry could follow the path of the poultry and pork industries and create more formal, better-funded research organizations so it could respond more quickly to problems like bird flu – or avoid them altogether.
The dairy industry could also combat the spread of disease by limiting the movements of lactating cows between states, Poulsen said.
The U.S. Department of Agriculture will begin testing soon a vaccine that could be given to calves, which protects the animals and also reduces the risk of illness among workers.
The egg industry is also hopeful that researchers can develop vaccines for poultry that could be fast, cheap and effective. Workers can't vaccinate the millions of chickens that may need a vaccine, but industry officials hope a vaccine can be distributed in the water the birds drink, in the pellets they eat or even before 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 a few people, Thompson said.
“Part of what is being developed right now is, what way can we vaccinate them that is cost-effective and disease-resistant?” said Thompson.
