Avian Flu Causes Major Adverse Impact in Dairy Herds

By Laura Reiley

A new paper from a team of Cornell researchers shows that the highly pathogenic avian influenza (HPAI) strain named H5N1 virus causes severe mastitis and decreased milk production in dairy cows, a drop-off that may extend beyond the clinical outbreak period.

The work describes the impact of HPAI to production parameters and its cost to the dairy industry.

Economic losses due to decreased milk production, mortality and early removal from the herd were estimated at $950 per clinically affected cow for a total cost of approximately $737,500 for just the one herd the team studied. This did not include any ongoing herd dynamics or reproductive losses for this herd.

In a paper titled “The impact of highly pathogenic avian influenza H5N1 virus infection on dairy cows” published July 15 in the journal Nature Communications, the researchers found cows clinically infected with HPAI presented a significantly increased risk of death and of premature removal from a herd of 3,876 adult cows in Ohio.

The most remarkable finding was the long duration of diminished milk production in clinically affected cows, said co-author Diego Diel, professor of virology in the Department of Population Medicine and Diagnostic Sciences and director of the Virology Laboratory at the Animal Health Diagnostic Center (AHDC), all in the College of Veterinary Medicine (CVM).