H5N1 bird flu outbreak in cows is likely widespread, milk tests show

In H5N1-infected cows, the first thing that tends to happen is their appetite disappears and their activity goes down. Then their milk production dries up. In some animals, the milk they do produce turns yellow and thick. “It’s an odd thing that seems to be unique to this particular virus,” said Keith Poulsen, director of the Wisconsin Veterinary Diagnostic Laboratory.