When Andy Miller, a rancher of nearly 40 years, spotted swelling around the navel of a 9-day-old heifer on Thursday, he feared the worst.
“I caught her up, brought her into the pen, and flipped her over, and I knew what I was going to find when I saw that swelling,” Miller said.
By Friday, the calf — named Esperanza — was infested with New World screwworm larvae.
“It smelled like rotten flesh, so right then I knew it wasn’t a simple navel infection,” Miller said.
The confirmed case is the first in Jim Hogg County and one of more than 20 reported across Texas as the flesh-eating parasite continues spreading through the region, prompting livestock quarantines and heightened concern throughout Texas’ $17 billion cattle industry.
“If they mature to 400 or 500 pounds, when you’re going to ship them and sell them, that’s a few thousand dollars a head,” Miller said. “People can’t afford to lose that kind of money. It’s people’s livelihood.”
Ranches step up inspections
About 50 miles north, Wyatt Ranches has increased inspections before cattle are loaded for transport in an effort to keep the parasite from spreading.
“I got to inspect every single animal unit that goes into this trailer,” Transportation Foreman Juan Ruiz Jr. said.
The added inspections require more manpower and could increase costs.
“It’s hard to inspect each and every one every day, so that’s gonna mean bringing in more people,” Ruiz said.
According to Division Livestock Foreman Aurelio Suarez Jr., female New World screwworm flies lay eggs in open wounds. Within 12 to 24 hours, those eggs hatch into flesh-eating larvae that feed on living tissue.
Dectomax gives ranchers another treatment option
If caught early, infected animals can be treated with an aerosol spray that prevents additional flies from laying eggs in open wounds.
Another option is Dectomax, an injectable treatment the U.S. Food and Drug Administration made more widely available under emergency measures earlier this year to help combat the outbreak.
Miller said he believes Dectomax is the better option for deeper wounds because it reaches larvae buried beneath the surface, where topical sprays may not.
After treating Esperanza, the calf has already shown significant, visible improvement.
“She’s gonna make it, I guarantee it,” Miller said after treating his calf.
Why this matters beyond the ranch
The growing outbreak comes at a particularly vulnerable time for the U.S. beef industry.
According to the latest U.S. Department of Agriculture cattle inventory report, the nation’s cattle herd has fallen to 86.2 million head — the smallest inventory since 1951. The historically low herd has tightened beef supplies and contributed to record cattle prices, with industry analysts expecting elevated beef prices to continue while producers rebuild their herds.
For ranchers like Miller, preventing additional losses has implications that stretch well beyond South Texas ranches.
“If they mature to 400 or 500 pounds, when you’re going to ship them and sell them, that’s a few thousand dollars a head,” Miller said. “People can’t afford to lose that kind of money. It’s people’s livelihood.”
Wildlife remains the biggest unknown
While ranchers can inspect and treat their cattle, Miller worries wildlife could allow the parasite to continue spreading through the Texas brush country.
“With all the animals having fawns, it’s that time of year. There’s got to be more cases already that we don’t even know, and there’s no way to patrol it, look after it or even try to do anything about it when it comes to the wildlife,” he said.
The Texas Animal Health Commission continues urging livestock owners to inspect animals regularly for unusual wounds or maggot infestations and report suspected New World screwworm cases immediately.