The United States has closed its border to Mexican cattle imports again, following a new spread of the deadly New World Screwworm (NWS) into parts of Southern Mexico. 

The decision, made on May 11, is part of an effort to protect the U.S. cattle industry but is already having a ripple effect on Texas feedyards and the broader livestock supply chain.

New infections were reported in Veracruz, Oaxaca, and Tabasco, marking the northward spread of the flesh-eating parasite. 

“The narrowest part of Mexico, geographically the Isthmus of Tehuantepec, has been considered an important line of defense… making effective control that much more difficult,” said Texas A&M AgriLife Extension Economist David Anderson.

The border had only recently reopened in February 2025 after being shut in November 2024. Since then, cattle imports had started to recover, averaging about 20,000 head weekly. 

However, Anderson notes that “imports have remained below 2024 and the previous five-year average” due to quarantine and inspection rules.

With only four of the U.S.’s 11 cattle ports open—most notably Presidio in Texas and Santa Teresa in New Mexico—the impact has been severe. Texas feedyards, including Kirkland Feedyard in Vega, are among those affected. 

“That’s the kind of customer you really work hard to work with, and now they can’t get cattle over here,” said owner Robby Kirkland, referring to a longtime Mexican supplier from Durango.