The flooding and record heat that have combined to shrink this year’s corn crop are feeding new calls from livestock producers to weaken the government’s ethanol mandates.

Producers told the House Agriculture Committee on Wednesday that tightening grain supplies are driving up feed costs further and threatening to push many poultry farms and others out of business.

“We have serious, immediate concerns about the availability and cost of feed ingredients caused by the mandated use of corn-based ethanol,” said Ted Seger, president of Farbest Foods Inc., a turkey producer in Indiana