Screwworms Screw with Beef Imports

Screwworms are screwing up beef imports from Mexico, and it will likely impact feeder cattle prices. 

After the discovery of a screwworm in Mexico on Friday, the USDA’s Animal and Plant Health Inspection Service (APHIS) announced it would pause animal imports from Mexico. 

Soundbite: “Even if the border opens soon the measures will be costly and it will impact cattle operations in the U.S. and Mexico for some time to come.” — Daniel Manzanares, director of the Santa Teresa International Export/Import Livestock Crossing in New Mexico

While only 5% of the U.S. feeder cattle supply comes from Mexico, Santa Teresa pens are already empty. On a typical day, they’d be filled with thousands of Mexican cattle before heading north. 

Fun fact: Almost 500K feeder steers and heifers cross the border through Santa Teresa annually, making it the largest livestock entry point in the U.S.

Worming their way in: The New World screwworm, a flesh-eating fly larva that attacks live tissue in cattle, hadn’t been seen in Mexico in 30 years. Earlier in November, Mexican officials detected a screwworm in a cow at Mexico’s border with Guatemala. The animal did not originate in Mexico.

No “fly” zone: APHIS doubled down on its efforts to control screwworms in 2006 and worked with Panama on a barrier zone. Central American countries have struggled with screwworms for a while, and the zone helped—until recently. Detections in Panama went from 25 cases per year to more than 6,500 cases in 2023. 

APHIS spends $110M to keep screwworms out of North America.