The u.s. Department of Agriculture Wednesday mandated testing for H5N1 of dairy cattle that cross state lines. The move is to protect the U.S. livestock industry from the threat of avian influenza.

Before interstate movement, dairy cattle are now required to receive a negative test for Influenza A virus at an approved National Animal Health Laboratory Network laboratory. Owners of herds in which dairy cattle test positive for interstate movement will be required to provide epidemiological information, including animal movement tracing.

USDA has identified spread between cows within the same herd, spread from cows to poultry, spread between dairies associated with cattle movements, and cows without clinical signs that have tested positive. On April 16, APHIS microbiologists identified a shift in an H5N1 sample from a cow in Kansas that could indicate that the virus has an adaptation to mammals. USDA has not found changes to the virus that would make it more transmissible to humans and between people.