A Second Idaho Dairy Herd Has Bird Flu. Here's What to Know

By Rachel Cohen

The U.S. Department of Agriculture confirmed a second Idaho dairy herd with avian flu late last week.

This herd, like the first group of cows that tested positive nearly three weeks ago, is at a farm in Cassia County.

Cows with the virus have reduced milk production and thicker milk consistency.

Unlike the first affected farm, which had recently imported cattle from Texas, the infected cows in this case have no connection to out-of-state cattle carrying the virus, according to the Idaho State Department of Agriculture.

Federal officials have determined that the virus is spreading from cow to cow, from cows back to poultry, between dairy farms through cattle movements and among cows not showing symptoms.

In response, ISDA has issued a quarantine on the second Cassia County farm, meaning no livestock are allowed in or out, and a ban on cattle and bison imports from out-of-state facilities where animals have tested positive remains in effect. ISDA said it recommends farmers test groups of at-risk cattle “whenever necessary,” and testing asymptomatic cattle is voluntary.

Rick Naerebout, the CEO of the Idaho Dairymen’s Association, previously said that it appeared the virus had been contained to the first Cassia County farm, as the eight sick cows there had recovered.

The Food and Drug Administration said this week it found nonviable viral evidence of the H5N1 bird flu in pasteurized milk, but stressed it believes milk is still safe to consume.