HPAI outbreak in Michigan dairy brings state total to 29 herds

Michigan Department of Agriculture and Rural Development Director Tim Boring has confirmed the detection of highly pathogenic avian influenza in a dairy herd in Shiawassee County, raising the total number of affected herds in Michigan to 29.

This case, initially identified by the Michigan State University Veterinary Diagnostic Laboratory, is pending further confirmation by the USDA’s National Veterinary Services Laboratories.

As of September 3, 197 dairy herds across 14 states have confirmed outbreaks of HPAI A (H5N1). The breakdown is as follows:

• Colorado: 64 herds
• Idaho: 30 herds
• Michigan: 28 herds
• Texas: 24 herds
• Iowa: 13 herds
• Minnesota: 9 herds
• New Mexico: 9 herds
• South Dakota: 7 herds
• Kansas: 4 herds
• California: 3 herds
• Oklahoma: 2 herds
• North Carolina: 1 herd
• Ohio: 1 herd
• Wyoming: 1 herd

»Related: Clinical signs and response to HPAI in dairy cattle herds

Biosecurity continues to be the most effective method of controlling HPAI outbreaks. On May 1, MDARD issued the Determination of Extraordinary Emergency HPAI Risk Reduction and Response Order (HRRRO), requiring all Michigan dairy farms to implement enhanced biosecurity measures. This includes a temporary ban on the exhibition of lactating and near-term pregnant cattle until no new cases are reported for 60 consecutive days. Dairy cattle from infected herds are prohibited from exhibition until further notice.

MDARD is collaborating with veterinarians and state and federal partners to monitor the health of affected herds and provide resources such as personal protective equipment to help mitigate the spread of HPAI. Key biosecurity practices, such as isolating new animals, daily health monitoring, and limiting non-essential farm visitors, remain critical to protecting dairy operations across the state.

»Related: Expert delves into the complexities of HPAI and milk consumption