A new study from Cornell researchers reveals that highly pathogenic avian influenza (HPAI) H5N1 virus causes severe mastitis and decreased milk production in dairy cows, leading to significant economic losses for the industry. The study found that clinically affected cows resulted in a total cost of approximately $737,500 per herd, with an average loss of $950 per cow.
Researchers observed that cows infected with HPAI presented a significantly increased risk of death and premature removal from herds. The virus also caused a long duration of diminished milk production in clinically affected cows, resulting in substantial financial burdens for dairy farmers.
According to co-author Matthew MacLachlan, the cost of removing a single cow from dairy production due to illness can be as high as $367, even if the cow recovers. However, outbreaks do not necessarily lead to price increases for consumers, as other factors such as marketing, packaging, and transportation also impact milk prices.
The HPAI outbreak has already cost the US poultry industry approximately $1.4 billion. To mitigate future outbreaks, researchers recommend implementing biosecurity measures and developing vaccines. The study’s findings highlight the need for further research on the virus’s impact on the dairy industry, given its widespread nature and evolving spread.
Source: https://news.cornell.edu/stories/2025/07/avian-flu-causes-major-adverse-impact-dairy-herds