Washington ? Agriculture Secretary Edward T. Schafer sparred with Senate lawmakers Thursday, insisting that regulations governing slaughterhouse inspections are sufficient to ensure the safety of the nation’s meat supply.

Schafer rejected senators’ calls to completely ban from slaughter any cattle unable to walk. “Downer” cows are at higher risk of carrying E. coli and Salmonella bacteria and of having the wasting neurological illness known as “mad cow disease.”

The stand-off came at a Senate subcommittee hearing triggered by practices at Westland/Hallmark Meat Co. of Chino, Calif., that led to the largest meat recall in U.S. history. Undercover video shot by the Humane Society of the United States showed downer cows being forced to slaughter by workers who poked them with electric prods or rolled them with forklifts.

Schafer resisted on all counts, insisting that current rules, when followed, are adequate.

“I don’t think it’s appropriate to have a 100 percent ban on down cows,” he said outside the hearing room, citing the costs to livestock producers.