### Bird Flu Outbreak Wreaks Havoc on California Dairy Farms

The latest H5N1 bird flu outbreak is causing more concern than anticipated at dairy farms in California's Central Valley. Veterinary experts and dairy farmers are alarmed by the much higher-than-expected mortality rate among infected cattle. While initial expectations pegged the mortality rate at below 2%, current observations indicate that between 10% and 15% of the infected cattle are dying.

Maxwell Beal, a Central Valley-based veterinarian, was taken aback by the severity of the outbreaks when he first encountered the disease in one of his herds. "It was just like, wow. Production-wise, this is a lot more serious than we had hoped. And health-wise, it's a lot more serious than we had been led to believe," Beal remarked. His concern was echoed by other veterinary professionals and dairy farmers during a recent webinar hosted by the California Dairy Quality Assurance Program.

The impact of the virus has extended beyond livestock health to humans as well. In Tulare County, which is responsible for around 30% of California's milk production with its over 600,000 dairy cows, two dairy workers are suspected to have contracted the H5N1 virus. This has heightened public health alerts, although state officials emphasize that the risk to the general population remains low.

Veterinarians like Beal and Murray Minnema are noting that the virus is far more pervasive than initially believed. Infection rates in some herds have reached between 50% and 60%, significantly higher than earlier reports of about 10%. Compounding the problem, cows infected with the virus are also experiencing complications like bacterial pneumonia and bloat, which stem from weakened immune systems and failure to eat properly.

Adding to the struggle is the recent bout of extreme heat, with temperatures soaring above 100 degrees since the end of August. "Heat stress is always a problem in dairy cattle here in California," Beal noted. The combination of heat and the virus, which affects the respiratory tract, is proving lethal to many cows.

Unfortunately, the repercussions are not just limited to the immediate symptoms. Beal and other experts are noticing that even after recovering from the virus, cows are only returning to about 60% to 70% of their regular production capacity. Some cows never fully recover and have to be removed from the herd altogether.

With no signs of abatement, this H5N1 outbreak is reshaping the landscape for dairy farming in California, thrusting both farmers and veterinary experts into a continual battle for their herds' wellbeing.