University of Minnesota Report: H5N1 Dairy Cow Study Finds Sustained Milk Production Drop, Extensive Transmission Across Herd

By Lisa Schnirring

Scientists who examined the impact of an H5N1 avian flu outbreak in an Ohio dairy herd that had about 3,900 cows found a milk production drop in clinically affected cows that lasted 60 days and extensive asymptomatic infections in other cows. The team, led by researchers at Cornell University, published their findings as a preprint study in Nature Portfolio.

The first illness in the herd was noted about 2 weeks after apparently healthy lactating cows from Texas were introduced into the herd. Decreased rumination and a decline in milk production appeared to decline about 5 days before clinical diagnosis.