Idaho is experiencing a notable uptick in H5N1 bird flu detections among dairy cattle, with 32 new confirmed cases reported in a 30-day window ending June 10, pushing the state’s total to 162 since the outbreak first emerged in March 2024.
Quarantine Numbers Climb
As of June 11, between 70 and 80 Idaho dairies were operating under quarantine — the most at any single point in the past year. State Veterinarian Scott Leibsle confirmed the scale of the situation, calling it “the highest number of affected dairies that we’ve had in a year.”
When H5N1 is confirmed through official testing, lactating dairy cattle on the affected facility are quarantined in place. Those animals continue milk production during the quarantine period, and state officials note that pasteurized milk from infected cows poses no human health concern.
National Picture
Idaho’s cases are part of a broader national outbreak that has now reached 1,141 confirmed cattle cases across 20 states. The pace has shifted considerably over time: 917 cases were recorded in 2024, followed by 171 in 2025, with 53 confirmed so far in the current year. Idaho’s recent 30-day surge, however, signals that activity in the state remains elevated.
Officials note that the H5N1 strain circulating in dairy cattle is distinct from strains found in migratory waterfowl, and no approved vaccine currently exists for cattle. The primary spread mechanism is movement of calves and cows between operations.
What Producers Should Watch For
The Idaho State Department of Agriculture has encouraged dairy operators to stay alert for symptoms including a drop in milk production, thickened milk, low-grade fever, and loss of appetite in their herds. Officials recommend strengthening biosecurity practices, exercising caution when purchasing livestock, and isolating any new animals for three to four weeks before introducing them to existing herds.
Leibsle expressed cautious optimism about the trajectory of the outbreak. “We’re hopeful that will be the case again as we get to the hot summer months,” he said, suggesting that warmer temperatures may help slow transmission, as has been observed in prior seasons.
Idaho Context
Idaho is one of the nation’s leading dairy-producing states, and the concentration of cases on dairies — 161 of the state’s 162 total confirmed cases — underscores how heavily the outbreak has centered on that sector of Idaho agriculture. The current quarantine load, while significant, allows operations to continue under state oversight rather than forcing shutdowns.
Producers and farm operators looking for updated guidance can monitor developments through the Idaho State Department of Agriculture. For Idaho’s dairy industry, the coming summer months will be a key indicator of whether the outbreak pace slows or continues at its current rate.
Category: Agriculture & Land
Tags: H5N1, bird flu, dairy cattle, Idaho agriculture, Scott Leibsle, livestock quarantine, ISDA