The mandate targeting bulk milk transporters and dairy processors is meant to help identify herds that have caught the virus, which has spread among livestock.

Highly pathogenic avian influenza H5N1 was first detected in dairy cattle in March. A recent federal order by the U.S. Department of Agriculture creates a five-stage National Milk Testing Strategy, complementing an order from April. Since March, bird flu has been detected in several Michigan herds and one farmworker.