Strengthening Biosecurity on Dairies: Best Practices for a Healthy Herd

As we continue to navigate Highly Pathogenic Avian Influenza (HPAI) H5N1 (Bird Flu) in our local dairy herds, reinforcing biosecurity protocols among employees and visitors remains critical. As of May 8, 2025, CDFA has confirmed a total of 771 infected dairies since the outbreak began in California. Over 600 of those dairies have been released from quarantine and Northern California still remains largely unaffected by HPAI H5N1 cases. Strengthening basic biosecurity practices is key for preventing HPAI H5N1 transmission but also for reducing the spread of other infectious diseases that threaten animal health and productivity. Here are some basic biosecurity recommendations:

Animal movement- It was clear that animal movement played a significant role in the HPAI H5N1 outbreak. Even if you’ve already navigated through the outbreak and have some level of herd immunity, it is still wise to evaluate animal movement protocols. Can newly arrived animals be isolated more effectively in the future? Can your daily procedures involve handling these animals last during daily chores? Is there a way to close the herd or limit animal movement? In an open herd, what other biosecurity practices can be implemented to mitigate the risk that animal movement poses? These are big questions that might not work for your facility but are worth pondering.

Visitors and traffic patterns- Vendors, consultants, haulers, and other visitors should understand they have a responsibility to adopt biosecurity practices, especially if they are visiting multiple farms on the same day. There should be a clear expectation that all visitors wear clean clothing and disinfected boots or disposable boot covers. Parking areas away from animal housing and handling areas should be used and visitors should not be driving around the dairy, especially in feed alleys. Higher risk traffic like rendering trucks should have a specific route that keeps them away from the herd.

Employee attire and PPE- Farm-specific boots and coveralls are a simple yet effective first line of defense to reduce the risk of pathogen transfer from employee clothing or footwear onto your dairy. Employee attire should remain on-site and be laundered at the facility. Such practices are especially important when employees work at multiple farm locations or share housing with individuals employed at other farms. Shared housing has been identified as a potential route for HPAI H5N1 transmission between dairy and poultry operations.

HPAI H5N1 is a zoonotic disease (meaning that it can spread from animals to humans) as are many other endemic diseases present on dairies. Personal protective equipment (PPE) should be used according to the level of risk present in the herd. While gloves are always mandatory for milkers, additional PPE should be worn when handling sick animals or milking cows during any disease outbreak. According to OSHA (Bird Flu Information for Employers), additional measures such as enhanced PPE use (protection for the eyes, nose, and mouth), biosecurity and PPE training, exposure controls, and written safety procedures are required in workplaces during the outbreak or quarantine.