Texas agriculture commissioner presses FDA to authorize feed-based ivermectin for NWS

Sid Miller, Texas Agriculture Commissioner, is urging FDA to authorize the use of ivermectin in medicated livestock feed, arguing that ranchers need faster, herd-wide options to slow a rapidly expanding New World screwworm (NWS) outbreak before it inflicts greater damage on the state's livestock industry.

In a request submitted on behalf of the Texas Department of Agriculture (TDA) and in coordination with the Texas Grain and Feed Association (TGFA), Miller asked the FDA for an Emergency Use Authorization (EUA) that would allow ivermectin to be incorporated into medicated feed and mineral supplements for cattle and other susceptible livestock. According to the TDA, feed-based delivery would also offer the only practical way to protect free-ranging deer and other warm-blooded wildlife from the parasite.

"Texas ranchers are fighting for their livelihoods and the security of the American food supply. They don't have time to wait," Miller said in the announcement.1 He noted that the parasite has already spread across multiple Texas counties within a matter of weeks, adding that "every day we delay is another day the [NWS] gains ground."

Building on injectable authorization

The request follows an earlier FDA emergency authorization permitting the use of injectable ivermectin,² a step Miller praised but described as insufficient for the scale of Texas ranching operations. Rounding up and injecting thousands of free-range cattle every few weeks, he argued, is not feasible while an outbreak continues to expand.¹

"Feed-based ivermectin would allow producers to protect entire herds quickly, efficiently, and with far less stress on both livestock and producers," Miller said. "Just as importantly, it gives us a practical way to extend protection to deer and other wildlife."

In the letter to Kyle Diamantes, JD, FDA acting commissioner, the TDA asked the agency to authorize ivermectin in medicated feed, establish appropriate dosing and withdrawal guidelines, and expedite its review in coordination with USDA. The Texas Grain and Feed Association has committed to manufacturing and distributing the medicated feed rapidly upon approval so producers could begin using it without delay.

"The infrastructure is already in place," Miller said.¹ "Our feed manufacturers are ready. Our producers are ready. The only thing standing in the way is federal approval."

An "all-of-the-above" approach

Miller has repeatedly called for a multipronged federal response to the outbreak, one that combines expanded sterile fly production, enhanced surveillance, aggressive treatment protocols, and additional emergency authorizations for proven livestock products. Feed-based treatment, in his framing, is one more tool alongside those already in use. "I've said from day one that this fight will require every arrow in the quiver," Miller said. "Sterile flies, suppression systems, inspections, injectable treatments, feed treatments—we need all of it."

NWS targets warm-blooded animals, including cattle, wildlife, pets, and, less commonly, humans. The parasite was eradicated from North and Central America decades ago but has advanced northward in recent years, reaching Mexico and, more recently, the US.

“The threat posed by [NWS] to Texas’s livestock producers — many of them multigenerational ranch families whose livelihoods depend on the health of their herds — demands the full deployment of every available tool. We are confident that FDA’s leadership, in partnership with TDA and TGFA, can move swiftly to authorize this essential prevention measure. We welcome the opportunity to discuss this request at your earliest convenience,” the letter concluded.³

dvm360 is continuing to follow NWS and its movements across the US, and is updating this article in real time with the latest information. dvm360 also now has a dedicated NWS landing page on our website, which can be accessed here.

Reference

1. Texas Department of Agriculture. Commissioner Sid Miller urges FDA to approve feed-based ivermectin to combat New World screwworm. Texas Department of Agriculture. Published July 1, 2026. Accessed July 6, 2026. https://texasagriculture.gov/News-Events/Article/11983/Commissioner-Sid-Miller-Urges-FDA-to-Approve-Feed-Based-Ivermectin-to-Combat-Ne
2. Bautista-Alejandre A. FDA-authorized and -approved animal drugs for New World screwworm. dvm360. June 8, 2026. Accessed July 6, 2026. https://www.dvm360.com/view/fda-authorized-and-approved-animal-drugs-for-new-world-screwworm
3. Miller S; Texas Department of Agriculture. Emergency use authorization request — ivermectin in medicated livestock feed for the prevention and control of New World Screwworm (Cochliomyia hominivorax) in Texas. Letter to: Kyle Diamantas, Acting Commissioner, US Food and Drug Administration. June 29, 2026. https://acrobat.adobe.com/id/urn:aaid:sc:US:165e2e97-4ec3-4ff7-87cd-bfe38be1f029