By Tom Polansek
CHICAGO (Reuters) – Dairy farmers in the United States are raising their defenses to try to contain the spread of avian flu: banning visitors, cutting down trees to discourage wild birds from landing and disinfecting vehicles entering their lands.
South Dakota on Thursday became the eighth state to find highly pathogenic avian influenza (HPAI) in a dairy herd, after the U.S. Department of Agriculture reported infections in North Carolina, Texas, Kansas, Ohio , Michigan, Idaho and New Mexico.
While the first cases appear to have been introduced into herds in Texas and Kansas by wild birds, the USDA said transmission among cattle is also possible. Agriculture officials in Michigan and Ohio said infected herds in those states received cattle from Texas.
Reuters spoke to seven dairy farmers in five states who said they were beefing up safety and cleaning procedures, with three producers exceeding government recommendations.
“Think of our farm now as a gated community for cows,” said Karen Jordan, who raises about 200 dairy cattle in Siler City, North Carolina. “Only the most essential person can pass the gate.”
Even before the North Carolina outbreak, Jordan, 64, had said he was limiting visitors who might unintentionally carry contaminated bird droppings on boots or vehicles. He has also started cutting down about 40 small trees to avoid attracting wild birds during their spring migration.
The first confirmed case in a dairy herd on March 25 and the second human case in two years on April 1 have heightened concerns in the United States about the spread of the virus to animals and people. Bird flu has decimated poultry farms around the world since 2022 and has infected mammals ranging from seals to foxes to skunks.
The US Centers for Disease Control and Prevention has said the risk to humans remains low, but has asked states for plans to test and treat potentially affected farm workers.
REDUCED MILK PRODUCTION
While bird flu is lethal to poultry, cows appear to recover. Outbreaks in dairy herds primarily affect lactating cows, the USDA said, reducing milk production and prompting farmers to isolate sick animals while keeping their milk out of the food supply.
Milk production in the United States grew to nearly $60 billion in 2022. Dairy producers now fear a drop in demand for milk and cheese, after the USDA reported avian influenza in untested milk samples. pasteurized, although agricultural officials say pasteurized milk is safe.
Milk futures prices fell as infections expanded last week, before the market recovered. Beef cattle futures also fell on fears of reduced demand, although there have been no confirmed cases of the virus in cattle raised for meat.
The USDA has not issued quarantine orders for infected dairy herds, but last week recommended minimizing movement of cattle and testing milk samples from lactating cows if they need to be moved. Producers were also urged to monitor livestock for diseases; isolate newly added cows; and keep wildlife and domestic animals such as cats away from agricultural buildings to reduce the spread of the virus.
The agency advised farmers to pay “particular attention to good milking practices, such as disinfecting equipment.” In interviews with Reuters, veterinary authorities raised the possibility that milking machines could play a role in spreading infections among cows, although this has not been confirmed.
“We cannot rule out other possible modes of transmission of HPAI, including equipment,” the USDA said in an email.
Seven state and industry officials said farmers face challenges because of uncertainty about how the virus is spreading and the exposure of outdoor barns to wild birds.
Idaho, North Carolina and more than a dozen states that have not confirmed cases in cattle have imposed additional shipping requirements to protect their herds.
Nebraska, the second largest U.S. cattle producer after Texas, on April 1 began requiring producers to obtain permits to bring breeding dairy cows into the state so officials can better track movements some animals.
Texas advised producers to monitor their herds and keep sick animals at home. Kansas has recommended limiting the movement of livestock but has not imposed additional restrictions, said Justin Smith, the state’s animal health commissioner.
“These dairies have a lot at stake,” Smith said in an interview. “If they have concerns about that movement, they need to reevaluate it, rather than me imposing a reevaluation.”
Yogurt maker Danone said it is advising suppliers to isolate cattle that may have been exposed to the virus and to report any cases to local officials.
TIRE DISINFECTION
In Fort Branch, Indiana, Steve Obert, 61, asks drivers to spray disinfectant on truck wheels before letting them enter his farm. He raises about 1,200 milk-producing cows for Dairy Farmers of America, a cooperative of more than 6,000 farms.
Obert, who is also executive director of the industry group Indiana Dairy Producers, said larger farms face greater risks, in part because they maintain large supplies of feed that attract wild birds that could carry the virus.
Large ranches also often ship heifers, or female cows that have not yet given birth, to other states to be fertilized before returning to their home farms for milking, he said.
Obert, who ships cows to Kentucky, said he trusts Indiana’s decision not to impose new restrictions on cattle movement, but: “As a producer, you sit on the edge of your seat thinking, ‘Man, I hope we’re not behind. ‘”
In Rockford, Illinois, 43-year-old farmer Pollard, who supplies milk to the cooperative Prairie Farms, is keeping a calf he bought for his daughter from Wisconsin in solitary confinement for 21 days.
No cases have been reported in Wisconsin, but Shelly Mayer, 58, said she is looking for dead birds at her farm outside Milwaukee and is working to keep water tanks clean of bird droppings and other contaminants.
Farmers are also trying to keep wild birds away from feed reserves, but it’s difficult.
“The dairy farm is like a giant bird feeder,” said Jamie Jonker, chief science officer of the National Dairy Producers Federation.