The South Dakota Department of Agriculture and Natural Resources is reporting avian influenza, or bird flu, was detected in a South Dakota dairy cattle herd.
DANR and the state Animal Industry Board, a board assigned to the state ag agency, announced Thursday the U.S. Department of Agriculture’s National Veterinary Services Laboratory confirmed a positive detection of the virus in the herd April 9. This is the first confirmed case of bird flu in a dairy farm in South Dakota.
Beth Thompson, South Dakota state veterinarian and head of the AIB, told the Argus Leader on Thursday positive samples were taken from more than one cow.
Unlike avian influenza tracking within U.S. poultry, the Animal and Plant Health Inspection Service, a sub-agency of USDA, has not revealed which county the positive tests originated from.
“We’re only going down as far as the state, mainly because we all want to protect the farmers and ranchers out there because there are fewer dairies that sit in some of these states,” Thompson said. “This is going to be ‘South Dakota 001.'”
According to APHIS, dairy herds in eight states have tested positive for the virus. As of Thursday, this list includes one Idaho herd, three Kansas herds, two Michigan herds, five New Mexico herds, one North Carolina herd, one Ohio herd, one South Dakota herd and 10 Texas herds.
Thompson said avian influenza has managed to afflict a number of other mammals, such as bears, seals and skunks, which points to its notorious ability to evolve and affect other species.
South Dakota’s poultry facilities have been hard-hit by the virus, which the USDA designates among meat and egg birds as highly pathogenic — near 100% death rates. Of the more than 82 million commercial birds culled due to avian influenza since February 2022, about 5.37 million of those birds were from South Dakota’s turkey, egg laying and even some upland game farms.
The spread of this strain of avian flu has been attributed to migratory wild birds, Thompson said. According to the Centers for Disease Control and Prevention, infected birds can shed the virus in their saliva, nasal secretions and feces.
“We’ve got birds flying over us right now, and it’s hard to say where they’re stopping and dropping off their contaminants,” Thompson said. “It’s concerning. Our dairies tend to be fairly open air.”
Still, Thompson found it “a little surprising” the virus has been discovered in cattle.
“There’s all of this evidence from the last two years of what this virus can do,” Thompson said. “We hope that this migratory season and whatever happened that some of this virus spilled over into cattle is a one-time event. But we can’t say that for sure.”
Because cows have not been widely dying off from the disease, avian influenza in dairy cattle is not considered highly pathogenic, Thompson said.
But the symptoms of the virus are still apparent, she added.
“The really big indicator is milk production drops completely,” Thompson said. “Feed consumption goes down, and I think water consumption has also been going down too. Of course, if those two things go down, you get a little bit different manure consistency.”
There’s also herd-wide impacts to consider. The state veterinarian said she’s heard of affected dairies temporarily losing milk production from 10% to 12% of their milk cows.
“These cows allegedly go back into milk and they go back into the the producing part of the herd, but I don’t know if they go back in producing the same amount of milk as they did before they were infected with the virus,” Thompson said.
More: Bird flu outbreak is an ‘evolving situation.’ Here’s what to know about symptoms, spread.
Producers are encouraged to enforce their biosecurity plans such as limiting visitors, separating new animals and sick animals, and cleaning pens, equipment, vehicles, clothing, footwear, and hands, the release states.
Dairies are required to ensure only milk from healthy animals enter the food supply chain. Additionally, anything labeled as “milk” must go through the pasteurization process, which includes heating the contents to a high temperature to kill harmful germs and pathogens.
“South Dakota Dairy Producers encourages all dairy producers to closely monitor their herd and contact their herd veterinarian immediately if cattle appear symptomatic,” Marv Post, Chairman of South Dakota Dairy Producers, stated in DANR and AIB’s joint Thursday press release. “USDA continues to emphasize that pasteurization kills the virus and that milk and dairy products are safe to consume.”
This article originally appeared on Sioux Falls Argus Leader: South Dakota dairy herd tests positive for bird flu
