WASHINGTON — Four senators directed a letter to US Agriculture Secretary Brooke Rollins, asking that the US Department of Agriculture’s (USDA) plan to combat highly pathogenic avian influenza (HPAI) encompasses not only chickens but also turkeys and dairy cattle.

Senators Chuck Grassley (R-Iowa), Amy Klobuchar (D-Minn.), Mike Rounds (R-SD) and Elissa Slotkin (D-Mich.) sent the letter on April 9, a little over a month after Rollins rolled out the USDA’s $1 billion bird flu mitigation plan.

The five-pronged approach sought to lessen the spread of HPAI while stabilizing the egg market after prices reached consecutive record highs. Less than a month into the plan, Rollins announced significant improvements, including a drop in wholesale egg prices of nearly 50%.

In their letter, the senators thanked Rollins for her commitment to addressing HPAI as a top priority.

“We … believe this strategic plan is an important first step in this effort,” they said.

However, the senators noted the need for extending measures to turkeys, dairy herds and wildlife. HPAI has impacted 160 million birds, including 18.6 million turkeys, as well as 1,000 dairy herds across the United States.

“While the plan did include shared priorities to continue combating this disease — including the expansion of relief to farmers dealing with outbreaks among their livestock and investment in research — we encourage the plan to include turkeys and dairy cows,” they wrote. “Since avian flu has impacted a wide array of animals, we believe any biosecurity and vaccine measures, including discussions with foreign trading partners, offered by the department should be available to all livestock producers dealing with avian flu, including turkey and dairy producers.”

The senators also requested a timeline for the USDA’s strategy of working with trading partners to ensure potential vaccination does not disrupt trade. They asked for another timeline for conditional approval of an HPAI vaccine for dairy cattle.