Weld County dairy tests positive for bird flu after two-year gap

A dairy farm in Weld County is under quarantine after tests confirmed the presence of Highly Pathogenic Avian Influenza. This marks the first such detection in Colorado in more than two years. The Colorado Department of Agriculture (CDA) identified the specific strain as H3.13. The National Veterinary Services Laboratory issued the official confirmation on Oct. 24. A sample from the facility had previously tested presumptive positive at the Colorado State University Veterinary Diagnostic Laboratory.

The detection follows a mandate introduced in 2024, when Colorado became a central point of a national bird flu outbreak. At that time, state agriculture officials required weekly testing of milk samples from all commercial dairy farms. This measure was the first of its kind in the United States. During the 2024 surge, the state recorded its first confirmed case in April. The outbreak eventually impacted 64 dairies. By December 2024, CDA reported that all affected facilities had been released from quarantine due to the monitoring effort.

Dr. Maggie Baldwin, the Colorado State Veterinarian, stated that the finding demonstrates the value of routine bulk milk tank testing. She said, “This detection underscores the importance of our routine bulk milk tank testing to keep our herds healthy and our food supply secure.” Baldwin added that the proactive monitoring ensures early detection leads to swift mitigation measures to protect consumers.

Under the current quarantine order, the dairy must restrict the movement of lactating cattle from the facility. The farm is also required to implement strict biosecurity protocols for all activity. Weekly testing of bulk milk tanks will continue until the farm achieves two consecutive negative results, with tests taken at least one week apart. CDA is collaborating with the Colorado Department of Public Health and Environment to monitor farmworkers and staff for potential exposure.

State officials said the risk to the general public remains low. Pasteurized milk is considered safe to consume. The CDA noted that people at the highest risk for avian flu are those with direct contact with infected birds or other animals.