Mexico resumes limited cattle exports to US after screwworm pause, relieving ranchers

AGUA PRIETA, Mexico (AP) — Mexico resumed live cattle exports to the United States on Monday after they were halted for nearly two years by restrictions imposed by the Trump administration following a screwworm outbreak .

Even under strict limitations, the reopening of the trade channel brought relief to Mexico's ranching industry, which was dealt an economic blow by the controls. The flesh-eating worm is now present on both sides of the border.

In the sprawling desert mountains along the U.S.-Mexico border, hundreds of cattle began to cross from the Mexican town of Agua Prieta in the state of Sonora to the Arizona town of Douglas at around 3 p.m.

The process began after several hours of inspections by Mexican and U.S. authorities, who used dogs to inspect each animal and determine that they were not infected with screwworm.

The larvae come from the Cochliomyia hominivorax fly, which invades open wounds or the mucous membranes of body openings in any warm-blooded animal, including humans, and devours tissue, causing the wounds to become increasingly deep and painful.

The pest arrived in Mexico in November 2024 and is now present in 30 of the country’s 32 states, including the northern state of Sonora. In the United States, the first cases began to be reported in June in the states of Texas and New Mexico.

Mexican President Claudia Sheinbaum celebrated the reopening on Monday morning, and her administration outlined precautions to beat back the outbreak. That included strengthening cattle tracing systems and continuing to disperse sterile flies in border states like Sonora and Chihuahua, the largest exporters of cattle to the U.S. Mexico currently has 1,937 active screwworm cases.

To resume exports from Mexico on Monday, the U.S. approved a new protocol that included placing radio-frequency identification tags in the cows’ ears and installing scanners to detect the tags.

Cattle crossings into Arizona were also limited to 700 head per day, increasing to 900 per day next week and 1,300 per day the following week.

While Mexico has hundreds of cattle ready for export, the Trump administration controls will slow recovery of the industry, leaving herds in the U.S. with the lowest cattle counts in 75 years, and a shortfall of about 1.2 million cows, which has led to a surge in beef prices.