US scientists hunt for answers as bird flu outbreak spreads among cows

FILE - Dairy cows stand in a field outside of a milking barn at the U.S. Department of Agriculture's National Animal Disease Center research facility in Ames, Iowa, Aug. 6, 2024. In this photo provided by the US Department of Agriculture, animal care staff prepare to collect a blood sample from a dairy calf vaccinated against bird flu at the National Animal Disease Center research facility in Ames, Iowa, July 31, 2024. FILE - Dairy cows stand in a field outside of a milking barn at the US Department of Agriculture's National Animal Disease Center research facility in Ames, Iowa, Aug. 6, 2024.

At first glance, it looks like an unassuming farm. Cows are scattered across fenced-in fields. A milking barn sits in the distance with a tractor parked alongside. But the people who work there are not farmers, and other buildings look more like what you'd find at a modern university than in a cow pasture.