Mexico Resumes Limited Cattle Exports to US After Screwworm Halt

Mexico resumed live cattle exports to the United States on Monday, ending a nearly two-year halt imposed by the Trump administration after an outbreak of the flesh-eating New World screwworm.

Hundreds of cattle crossed from Agua Prieta, in the Mexican state of Sonora, to Douglas, Arizona, around 3 p.m. following hours of inspections by Mexican and U.S. authorities, who used dogs to check each animal for signs of infection.

The screwworm's larvae, which come from the Cochliomyia hominivorax fly, invade open wounds or mucous membranes of warm-blooded animals, including humans, devouring tissue and causing increasingly deep and painful wounds. The pest reached Mexico in November 2024 and has since spread to 30 of the country's 32 states, including Sonora. The first U.S. cases were reported in June in Texas and New Mexico.

Mexican President Claudia Sheinbaum celebrated the reopening Monday morning. Her administration said it would strengthen cattle tracing systems and continue releasing sterile flies in border states such as Sonora and Chihuahua, the country's largest cattle exporters to the U.S. Mexico currently has 1,937 active screwworm cases.

To allow exports to resume, the United States approved a new protocol requiring radio-frequency identification tags in cattle's ears and scanners to detect them. Crossings into Arizona were capped at 700 head per day, rising to 900 next week and 1,300 the week after.

While Mexico has hundreds of cattle ready for export, the restrictions will slow the industry's recovery. U.S. herds are at their lowest levels in 75 years, with a shortfall of about 1.2 million cows that has helped drive up beef prices.