R-CALF USA is calling on the FDA to approve ivermectin to help protect livestock from the possible spread of New World screwworm in the U.S.
The group says that feed-grade ivermectin is a proven tool to protect domestic herds and wildlife, especially in southern border states.
They highlight the success of the drug in limiting the spread of cattle fever tick.
“The potential impact on the United States livestock markets would be immensely negative if an actual case of New World screwworm was identified in the USA. Until an adequate response with gamma ray irradiation of male screw worm flies can be implemented, the feeding of ivermectin is a very real defense.”
The request follows false reports that New World screwworm was found in Missouri. That claim caused a downturn in cattle futures markets and is now being investigated by the state of Missouri.
“USDA can no longer keep wasting its time and personnel to deploy Commissioner Miller’s infamous traps, which USDA has deployed, tested, and has proven ineffective.”
October 14, 2025 01:19 PM
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“Good flies? Is that like a good fire ant?” Miller said. “I don’t know what a good fly is. I don’t know if they’re afraid to kill house flies or stable flies, but I’m ready to kill the screwworm fly.”
October 13, 2025 01:28 PM
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Large animal veterinarian Dr. Rosalyn Biggs with Oklahoma State University warns producers may not be prepared for the real threat of New World Screwworm.
October 09, 2025 01:10 PM
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Mexico’s tougher, two-step treatment and added checkpoints are catching cases before they can spread—good news for producers near the border.
October 07, 2025 10:55 AM
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October 01, 2025 10:02 AM
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Farmers will need to closely monitor forecasts if the regulatory changes are implemented, as temperature cutoffs will replace fixed spray dates.
September 30, 2025 04:39 PM
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