A mystery illness afflicting dairy cattle in Texas has been identified as highly pathogenic avian influenza.
The U.S. Department of Agriculture confirmed on March 25 that two dairy herds in Texas and two in Kansas tested positive for bird flu. The flu was believed to have come from wild birds. The USDA said the illness does not seem to be transmitted from cow to cow within the same herd.
The USDA said “At this stage, there’s no concern to the safety of the commercial milk supply” as milk from sick animals is diverse or destroyed. Additionally, pasteurization has proven to inactivate bacteria and viruses, like influenza, in milk.
The disease seems to affect mostly older dairy cows. According to the Texas Department of Agriculture, impacted cattle show flu-like symptoms including fever, low appetite, thick and discolored milk along with a sharp reduction in milk production averaging between 10-30 pounds per cow throughout the herd.
“Economic impacts to facilities are ongoing as herds that are greatly impacted may lose up to 40% of their milk production for 7 to 10 days until symptoms subside,” the Texas Department of Agriculture said.
Alerts had gone out about a mystery illness impacting dairy cows in the Texas panhandle from dairy groups and extension educators elsewhere in the country. Pennsylvania’s Center for Dairy Excellence sent an email on March 19 about an unknown illness impacting Texas dairy cattle, urging local dairy producers to check their biosecurity measures.
It was initially reported that about 10% of cows within a herd appeared to be clinically affected, with little to no mortality. Most cows recover from the illness.
Texas Ag Commissioner Sid Miller said unlike with poultry hit by the bird flu, there is no need to depopulate impacted dairy herds.
In a joint statement from the National Milk Producers Federation, International Dairy Food Association, Dairy Management Inc. and the U.S. Dairy Export Council, producers were urged to increase their biosecurity protocols. The groups referred to the National Dairy FARM Program for biosecurity tips.
Other livestock infections
Last week, the Minnesota Board of Animal Health announced a goat kid in Minnesota had tested positive for highly pathogenic avian influenza. This was the first case of bird flu detected in domestic ruminants in the U.S.
“The owner notified the Board of unusual deaths of newly kidded goats on the property where a backyard poultry flock was depopulated due to HPAI in February,” the Minnesota Animal Health Board said in a statement released March 20. The goats and poultry had access to the same space, including a shared water source.
The University of Minnesota Veterinary Diagnostic Laboratory confirmed one of the deceased goat kids tested positive bird flu. Samples for adult goats were negative and all appeared healthy, the board said.
There have been more than 200 detections of bird flu in mammals in the U.S. since the outbreak began in February 2022.
More than 82 million domestic birds in 1,115 flocks have been culled as a result of the current bird flu outbreak. The last detected case in Ohio was Feb. 27 in a backyard flock in Mahoning County. More than 9.6 million birds from 7 commercial flocks and 10 backyard flocks have been culled in Ohio during this outbreak.
The last detected case in Pennsylvania was Feb. 12 in a backyard flock in Schuylkill County. More than 4.7 birds in 32 commercial flocks and 38 backyard flocks have been culled in Pennsylvania during the current HPAI outbreak.
Detections tend to be higher in the fall and spring as wild birds that naturally carry the virus migrate and spread it in their droppings.
