DEKALB, Ill. — This agricultural town is nicknamed Barb City because the spiky wire was perfected here. But the mayor receives postcards from animal-rights activists saying it should be called the city of barbarians.

DeKalb is home to the last remaining plant in America where horses are slaughtered for human consumption. Except for a portion sold to U.S. zoos, the horse meat is shipped to be eaten by diners overseas. The state banned such slaughters last month. A temporary order allowing Cavel International Inc. to operate expired today.

“It’s a black mark on the community. It’s a stigma,” said slaughterhouse opponent Gail Vacca, who moved her horse training business away from DeKalb because she said owners were worried their animals would be kidnapped and sold to the plant. “DeKalb is a lovely community. It’s horrible they’ve been stigmatized by this nasty industry.”

Cavel lawyers say the Illinois law violates the interstate and foreign commerce clauses of the U.S. Constitution because it also bans importing or exporting horsemeat for human consumption.

Two other U.S. plants, both in Texas, closed earlier this year. A federal appeals court upheld a Texas law banning horse slaughter for the sale of meat for food, and the U.S. Supreme Court refused to take up the case.