Taking a page out of Colorado’s book, USDA will start testing bulk raw milk around the country for highly pathogenic avian influenza (HPAI). The department said last week that testing would begin in early November.
Milk silos will first be tested in states where the H5N1 virus has been identified; bulk sampling will then be rolled out in states where H5N1 has not yet been confirmed. If bulk samples test positive, testing will be narrowed down to the farm level to better track and monitor the disease. Farm testing will continue until herds in an area are confirmed virus-free.
Since May, USDA has required that lactating cattle be tested for the virus before moving between states. But last month, the U.S. Animal Health Association passed a resolution emphasizing the need for a coordinated state and federal surveillance plan that called the interstate testing requirement “inadequate.”
The American Association of Bovine Practitioners (AABP) has echoed that sentiment. Also, less than 1% of the nation’s dairy herds have enrolled in USDA’s voluntary HPAI herd testing program.
The virus has slowed its spread since the spring, and new cases have been confirmed in just three states — California, Idaho, and Utah — in the last 30 days. However, there were 160 cases identified in those states, and the disease had not previously been found in Utah.
Colorado implemented mandatory weekly milk testing for HPAI in July after the number of detected cases in dairy, poultry, and humans ramped up. In all, the virus was confirmed in 64 of the state’s 110 dairies, but no new cases have been identified since the end of August.
There have been 223 confirmed cases of HPAI in California since the disease was first identified there in August. The nation’s largest dairy state now represents more than half of the country’s total confirmed cases, and roughly 20% of the state’s herds have been affected.
In announcing the move, USDA reminded the public that it has a precedent with successful bulk tank milk testing efforts, such as the work that eradicated brucellosis from dairy farms. The department will continue to work with state and local veterinarians to carry out the testing.
Biosecurity efforts that limit the movement of animals, equipment, and people between farms remain a dairy farmer’s best bet against introducing the disease to their operation. Two potential H5N1 vaccines are currently undergoing field trials.
