USDA Reopens Border to Mexican Cattle as Screwworm Reaches US Wildlife

USDA will reopen the Columbus, New Mexico, port to Mexican cattle imports even as New World screwworm has surfaced in American wildlife for the first time — an elk harvested by a hunter on a game ranch in Pecos County, Texas.

The Animal and Plant Health Inspection Service confirmed the parasite in the elk, and on the same day New Mexico's Department of Agriculture confirmed a case in a beef cow in Otero County. The back-to-back detections mark a new phase in an outbreak that has already disrupted cattle trade across the southern border.

Texas officials are redrawing the state's infested zone around the elk detection. USDA and Texas Parks and Wildlife are expanding surveillance in the surrounding area.

New Mexico has moved faster. The state established a quarantine zone with a radius of at least 12.5 miles around the infected cow. Animals inside that zone must be inspected before moving, and treated if necessary.

What does the wildlife case change for producers?

Plenty. Deer, elk and other free-ranging animals "don't stop at fences or checkpoints," officials noted, which means the parasite now has a reservoir that livestock controls cannot contain through quarantine lines alone.

For ranchers, that translates into sustained risk to herd health and treatment costs even if domestic herds stay clean. Screwworm poses no food safety risk, USDA emphasizes, but it can inflict serious damage on livestock production — infected animals suffer wounds infested with maggots that can prove fatal if untreated.

Officials are urging hunters this fall to serve as an early-warning network. Hunters should watch for:

• maggots in wounds
• foul-smelling injuries
• weak, isolated animals

Anything suspicious should be reported immediately.

When do the border crossings reopen?

The Columbus, New Mexico, port is scheduled to reopen to cattle imports under APHIS's phased reopening plan. That plan began in Arizona in August, and Nogales, Arizona, is next — targeted for November 30, if conditions remain favorable.

The reopening schedule signals USDA's judgment that trade can resume despite the parasite's spread on the U.S. side. The agency has not indicated that the wildlife detection will slow the timeline.

Crossing volumes remain below historical averages, according to Don Close, senior animal protein analyst with Terrain. But he expects numbers to climb as the industry normalizes.

That normalization matters for U.S. feeder cattle supply. Mexican imports have historically supplemented domestic feeder numbers, and the longer crossings run below average, the tighter the pressure on feedlot placements and cattle prices.

What comes next?

Surveillance expansion in Texas, the New Mexico quarantine, and the November 30 target for Nogales are the markers to watch through the end of the year. The wildlife reservoir means eradication now depends partly on hunters and wildlife agencies, not just livestock inspection at the border.