"For decades, cowboys known as 'tick riders' have patrolled the U.S.-Mexico border to prevent cattle carrying 'fever ticks' from entering."
"LAREDO, Texas — The two cowboys knew the Red Angus calf could be trouble as soon as they spied it cowering behind a green patch of mesquite near a bluff north of the Rio Grande.
The calf did not belong here. This land has been closed to cattle for years, and the calf might have crossed in from Mexico where ticks carry a parasite that can kill up to 90% of a herd north of the border.
It was up to the cowboys, federal inspectors known as "tick riders," to capture the calf and figure out where it came from.
Some border agents hunt down drug smugglers or illegal immigrants. Tick riders look for undocumented cattle."