Wisconsin Confirms First Bird Flu Case in Dairy Cattle: Dodge County Herd Tests Positive

# Wisconsin Confirms First Bird Flu Case in Dairy Cattle: Dodge County Herd Tests Positive Wisconsin has confirmed its first-ever case of highly pathogenic avian influenza (HPAI) H5N1 in dairy cattle, ending the state's status as one of the few major dairy states to avoid the virus since it first appeared in U.S. herds in March 2024. The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) announced the detection late on December 14, 2025, after a milk sample from a dairy herd in Dodge County tested positive for the virus. --- ## Detection Through Routine Testing The infected herd was identified through Wisconsin's mandatory milk testing program, which the state implemented in May 2025 as part of the USDA's National Milk Testing Strategy (NMTS). According to Wisconsin State Veterinarian Darlene Konkle, the Wisconsin Veterinary Diagnostics Laboratory first reported a positive milk sample from the farm on Thursday, December 12. A subsequent test on Friday also returned positive results, with both tests confirmed by the USDA's National Veterinary Services Laboratory. Notably, five previous bulk tank samples from the same farm had tested negative, and Konkle told Wisconsin Public Radio that no new animals had been introduced into the herd. The cows were not displaying obvious signs of illness, "giving the farmer no reason to suspect highly pathogenic avian influenza on the farm." --- ## Farm Quarantined, Milk Supply Safe The affected farm, which has not been publicly identified, has been placed under quarantine. Any cattle exhibiting signs of illness will be separated for treatment and monitoring. Federal and state officials emphasize that there is no risk to consumers from the commercial milk supply. All dairy products are pasteurized before entering the market, which eliminates the virus. The Centers for Disease Control and Prevention (CDC) considers the human health risk from H5N1 to be low for the general public, though farm workers with direct animal exposure face elevated risk. DATCP is coordinating its response with the USDA, FDA, CDC, and state partners. --- ## Wisconsin's Dairy Industry Context Wisconsin ranks second nationally in milk production and is home to approximately 6,000 dairy farms. The state had been among a shrinking group of major dairy states—alongside states like New York and Pennsylvania—that had avoided dairy herd infections since HPAI first appeared in Texas and Kansas cattle in March 2024. Nationwide, 18 states have now reported dairy cattle infections. In 2025 alone, bird flu has been detected in dairy herds in Arizona, California, Idaho, Michigan, Nevada, Texas, and now Wisconsin. According to USDA data, only one other U.S. dairy herd (excluding Wisconsin) has tested positive in the last 30 days. --- ## Poultry Outbreaks in Nearby Counties While the dairy detection is Wisconsin's first, the state's poultry industry has been significantly impacted by bird flu in 2025. In September 2025, a commercial poultry operation in Jefferson County—just south of Dodge County—was forced to cull over 3 million egg-laying hens after testing positive for HPAI. Less than a week later, a nearby facility on the same property also tested positive, resulting in the destruction of an additional 493,298 pullets. The affected operation, Daybreak Foods Inc., is the fourth-largest egg producer in the United States. More recently, on December 9, a backyard flock in Marquette County, adjacent to Dodge County, also succumbed to the virus. --- ## Signs of HPAI in Dairy Cattle DATCP encourages all dairy producers to monitor their herds closely. Signs of HPAI infection in dairy cattle include: - **Changes in manure**: Often reported to be dry, tacky, or abnormal consistency - **Reduced feed intake**: With concurrent decreased rumen motility - **Drop in milk production**: Herd-level production declines or increased milk conductivity; affected cows may produce little to no milk - **Thicker, concentrated milk**: Unusual consistency Cattle and poultry owners are encouraged to practice strict biosecurity and register their premises with the state. Wisconsin law requires all livestock owners to register where their animals are kept, which helps animal health officials communicate quickly during disease outbreaks. --- ## Federal Response and Vaccination Push A bipartisan group of 23 U.S. Senators, representing states with significant agricultural interests including Iowa, Minnesota, South Dakota, and Virginia, is urging the USDA to prioritize and expedite a comprehensive bird flu vaccination strategy for poultry and livestock. The federal government continues genetic sequencing and on-farm investigations to better understand transmission patterns and develop containment strategies. --- ## What Producers Should Do Wisconsin dairy and poultry producers are urged to: 1. **Register premises** with DATCP to receive timely outbreak communications 2. **Practice strict biosecurity** to prevent virus introduction 3. **Monitor herd health** daily for any signs of illness 4. **Report signs of illness** immediately to DATCP at (608) 224-4872 during business hours or (800) 943-0003 after hours and weekends For more information, visit the [DATCP Animal Disease Reporting webpage](https://datcp.wi.gov/Pages/Programs_Services/AnimalDiseases.aspx). --- *Source: [Wisconsin State Farmer](https://www.wisfarmer.com/story/news/2025/12/14/wisconsin-confirms-bird-flu-in-a-dairy-herd-for-the-first-time/87770471007/)* *This is a developing story. We will update this article as more information becomes available.*