Like his father and grandfather before him, Mr Ibarra Vargas has raised cattle on the parched soil of Sonora, the state in northwestern Mexico that shares a long border with the US.
His family has faced punishing droughts before, but is now facing a new scourge: the new world screwworm, a flesh-eating parasite.
US agriculture officials halted live cattle crossing the border in July — the third suspension of the past eight months — due to concerns about the flesh-eating maggot that has been found in southern Mexico and is creeping north.
The screwworm is a larva of the Cochliomyia hominivorax fly that can invade the tissues of any warm-blooded animal, including humans.
The parasite enters animals’ skin, causing severe damage and lesions that can be fatal.
Infected animals are a serious threat to herds.
The US Department of Agriculture calls it a “devastating pest” and said in June that it posed a threat to “our livestock industry, our economy, and our food supply chain”.
It has embarked on other steps to keep it out of the US, which eradicated it decades ago.
As part of its strategy, the US is preparing to breed billions of sterile flies and release them in Mexico and southern Texas.
The aim is for the sterile males to mate with females in the wild who then produce no offspring.
The US ban on live cattle also applies to horses and bison imports.
It hit a ranching sector already weakened by drought and specifically a cattle export business that generated $US1.2 billion ($A1.9 billion) for Mexico last year.
This year, Mexican ranchers have exported fewer than 200,000 head of cattle, which is less than half what they historically send in the same period.
For Mr Ibarra Vargas, considered a comparatively small rancher by Sonora’s beef-centric standards, the inability to send his calves across the border has made him rethink everything.
The repeated bans on Mexican cows by US authorities have pushed his family to branch into beekeeping, raising sheep and selling cow milk.
What he earns is just a fraction of what he earned by exporting live cattle, but he is trying to hold on through the lean times.
“Tiempos de vacas flacas” — times of the lean cows — as he calls them.
“At least it lets us continue ranching,” the 57-year-old said, with a white cowboy hat perched on his head.
Even as ranchers in Sonora intensify their efforts to make sure the parasitic fly never makes it into their state, they’ve had to seek new markets.
