Cows that were too sick to stand up might have been butchered at a California slaughterhouse and entered the food chain, its president conceded Wednesday during a congressional hearing into the largest beef recall in U.S. history. 

Testifying before a U.S. House committee, Westland/Hallmark Meat Co. president Steve Mendell was compelled to watch a video showing crippled and sick animals — dubbed "downer cows" because they can't walk — being forced into the box at the Chino, Calif., plant where animals were normally slaughtered.

Panel chairman Representative Bart Stupak, a Michigan Democrat, then asked Mendell whether it would be logical to conclude from the video that downer animals had been butchered.

"That would be logical, yes, sir," Mendell said.

"Has your company ever illegally slaughtered, processed or sold a downer cow?" Stupak asked.

"I didn't think we had, sir," Mendell replied.

Mendell was called to testify at a previous hearing but didn't appear. The U.S. House's energy and commerce investigative subcommittee is looking into the recall of 64.4 million kilograms of frozen beef in February.

The recall was prompted by an undercover Humane Society video showing downer cows being dragged by chains, jabbed by forklifts and given shocks.

When the recall was issued, U.S. Agriculture Secretary Ed Schafer said the government had evidence that the company failed to bring in a veterinarian to treat cattle that had passed inspection but subsequently could not walk. That violated health regulations.

Earlier Wednesday, Mendell had said in a written submission that the downer cows "were not slaughtered, ground or sold. They were euthanized and removed."

But he did agree that the video was upsetting. "While these cows should be treated humanely and they were not, these cows were not harvested and they did not enter the food supply."

He said the recalled beef had not caused any illnesses.

Mendell said the company was ruined, and the 220 employees will lose their jobs. He said he'd received death threats. 

Two workers shown on the video are facing animal cruelty charges.

With files from the Associated Press