Idaho officials say high‑path avian influenza reached dairy cattle; state focusing on milk testing and targeted quarantines

Chanel Tewalt, director of the Idaho State Department of Agriculture, and Dr. Scott Lively, administrator of the Division of Animal Industries and state veterinarian, told the House Agricultural Affairs Committee that Idaho has shifted to a policy of targeted quarantines and milk testing after identifying HPAI in dairy cattle.

Tewalt said the department “very, quietly turned off basically the movement system” early in the outbreak to limit possible imports from affected states and to buy time to understand the disease's behavior. She told lawmakers the state emphasized farm‑level responses and “tried to have quarantines and restrictions that made sense to industry, that allowed them to move culls, that allowed them to move milk, that kept businesses moving while at the same time trying to help us get our arms around disease mitigation.”

Dr. Lively said the state has focused restrictions on lactating animals because the virus has been reliably detected in milk. “We know that the disease is primarily existing in the milk,” he said, and added that movement restrictions have been limited to lactating cattle; dry animals, calves and animals moving direct to slaughter have not been broadly restricted.

Why it matters: dairy producers measure production daily, so drops in milk quickly reveal disease at the herd level. Idaho officials said that approach let them detect and manage cases with a narrower economic impact than sweeping depopulation orders. The officials also said the state has pressed USDA for clearer federal guidance and that Idaho’s early, farm‑level approach differed from some federal responses.

Key details and timeline - Idaho restricted movements early in the event after reports from Texas, Kansas and New Mexico; the state closed or limited movement channels before some neighboring jurisdictions took similar steps, according to Tewalt. - A dairy that had already imported cattle before the restrictions produced the state's first positive detection in cattle; Tewalt said that farm “didn't do anything wrong” and was infected before Idaho's restrictions were in place. - Milk testing has been implemented statewide as part of a surveillance strategy. Tewalt said the testing program intends to give consumers confidence and help identify infected facilities. - Dr. Lively reported that, nationally, nearly all recent domestic‑livestock detections have been in cattle (he cited 977 cattle and one alpaca in a national summary) and that Idaho has had multiple dairy quarantines in the past year (he said 35 dairies had been quarantined previously and one was under quarantine at the time of the meeting).

On transmission and severity - Tewalt said Idaho was among the first to raise the possibility of cattle‑to‑cattle transmission and that recognition allowed producers to change biosecurity and herd management practices. She told the committee that early industry cooperation — dairymen, beef producers and Farm Bureau — supported targeted measures. - Dr. Lively said clinical severity has declined since the spring peak: animals identified in the fall and winter had milder or no noticeable symptoms compared with the “very sick” animals seen during the May–June peak, and he said that pattern suggests some build‑up of herd immunity.

Vaccines and federal trade implications - Both officials warned that vaccination decisions involve trade and international market considerations. Tewalt said some parts of industry fear vaccination could change the U.S. trade classification for poultry, with ripple effects for exports and imports; Lively said no approved cattle vaccine was available at the time.

Other species and ongoing surveillance - Lively said wildlife remain a reservoir and that the virus cannot be eliminated while migratory waterfowl carry it. He noted reports of infections in a few non‑poultry species elsewhere (for example cats and isolated mammalian cases in other states), and that ongoing genomic sequencing helps monitor for changes that could affect mammals.

What the committee was told next: Idaho officials said they will continue milk testing, apply quarantines only where supported by evidence, and press USDA for clearer national guidance tailored to dairy‑state realities.

Ending: Department officials asked lawmakers to direct constituents seeking information to state resources and to ISDA staff, noting the department and the state veterinarian can provide the most up‑to‑date, local guidance.