Michigan Dairy Farm Struggles with Long-Term Impact of H5N1 Avian Flu Outbreak on Milk Production and Herd Health

The first signs of trouble came in April when Brearley's monitoring system alerted him to rising temperatures in his herd. Soon, nearly half of his cows showed symptoms of illness, with five percent of the herd ultimately needing to be culled.

Milk production, which averaged 95-100 pounds per head before the outbreak, plummeted to 75 pounds per cow and has yet to fully recover, despite Brearley's efforts. The farm also suffered significant reproductive challenges, with cows aborting their calves early in the outbreak.

The source of the infection remains unclear, although a nearby egg-laying facility also tested positive for H5N1 and had to depopulate millions of birds.

Brearley estimates the outbreak cost him $100,000 in losses and additional labor expenses, with the long-term impact on his animals still unknown.

While Pennsylvania dairy farms have so far been spared, state veterinarians are urging more farms to participate in voluntary monitoring programs. For Brearley and others like him, the experience underscores the importance of preparedness and testing to mitigate the devastating effects of future outbreaks.