USDA APHIS confirmed an H5N1 clade 2.3.4.4b D1.1 detection in a Wisconsin dairy herd, announced on 14 December 2025. Sequencing indicates a new, separate spillover from wildlife, and no additional herds have been linked to it so far.
USDA states the detection does not affect the safety of the commercial milk supply.
Because milk from affected herds is diverted and pasteurization inactivates the virus, the price effect on milk and dairy feed demand should be limited. Further herd spread would be the main risk to dairy output.
After 22 past neutral disease events, Milk (Class III) moved a median -0.1% over 5 sessions (41% higher; middle half -1.4% to +0.5%), and +0.2% over 20.
Moves of each commodity's benchmark from the last close before the event. Historical reads pool past events of the same kind; they describe what happened, not what will. Not investment advice.