In Nevada, 3 of 11 silo samples collected on January 6 and 7, 2025 tested positive for HPAI via polymerase chain reaction (PCR) at the National Veterinary Services Laboratories (NVSL) on January 10. The state was notified, triggering an investigation to trace the source, as up to 12 dairies (in the same geographic region) could have contributed milk to the affected silos. On January 17, regulatory officials collected on-farm bulk milk samples from suspected dairy farms and submitted them to the Washington Animal Disease Diagnostic Laboratory (WADDL), a member of the National Animal Health Laboratory Network (NAHLN). HPAI was confirmed via PCR at NVSL on Friday, January 24, in samples from two of those dairies. NVSL completed whole genome sequencing on January 31 and identified HPAI H5N1, clade 2.3.4.4b, genotype D1.1 in samples from four different bulk tanks from one herd. A second herd also showed a partial sequence consistent with D1.1. Clinical signs were not observed in the cattle prior to the detection, but have been reported since, and the affected dairy producers reported large wild bird die-offs near the dairies.