Avian Flu Exacts Heavy Financial Toll on Dairy Industry, Report Says

By Mary Van Beusekom

Decreased milk production, death, and early removal from a single herd of adult dairy cows infected with the H5N1 strain of highly pathogenic avian influenza (HPAI) cost an estimated $737,500, even before considering ongoing altered herd dynamics or reproductive losses, according to a study published this week in Nature Communications.

Cornell University researchers evaluated the effects of HPAI on a herd of 3,876 dairy cows living on a farm in Ohio that experienced an outbreak in spring 2024 after the transfer of 42 healthy-looking lactating cows from a Texas farm. The team analyzed animal- and herd-level data collected before, during, and after the outbreak (March 8 to June 7). 

The ongoing US HPAI outbreak began in 2022, leading to the deaths of nearly 175 million birds. The virus spilled over into mammals and, in March 2024, dairy cattle. So far, 1,074 herds in 17 states have been infected.

Infected cows 6 times more likely to die

When the outbreak began on the Ohio farm, 3,433 of 3,876 cows (88.6%) were lactating. In total, 777 cows (20.0%) were diagnosed as having flu based on severe mastitis (inflammation of breast tissue) leading to a drop in milk production, loss of appetite, apathy, and decreased rumination time. Sick animals were segregated to a hospital pen next to those used for healthy non-lactating cows.