Cheese makers that rely on foreign sales are suffering as China and Mexico raise tariffs on U.S. mozzarella and provolone.

BelGioioso Cheese Inc., a second-generation family company in Wisconsin, has seen sales to Mexico drop since officials there implemented tariffs of up to 15% in early June on most U.S. cheese. The levies were a response to tariffs the U.S. placed on Mexican steel and aluminum.

On Thursday, Mexico was slated to raise its levy on most U.S. cheese to as much as 25%, while China on Friday is implementing tariffs on $34 billion of U.S. goods, including cheese and whey, a dairy byproduct often fed to livestock.

“It’s a nightmare,” said BelGioioso President Errico Auricchio.

Milk consumption in the U.S. has been falling for decades, prompting dairies to turn more of it into cheese. To sell it all, farmers have aggressively marketed their products to growing middle-class populations in Mexico and Asia.