(NaturalNews) Secretary of Agriculture Ed Schafer has rejected calls to ban downer cattle from the U.S. food supply.Downer cattle are those too sick or injured to stand. Because these cows are at a higher risk of carrying the fatal, incurable neurological disorder known as bovine spongiform encephalopathy, or mad cow disease, the USDA prohibited their slaughter in 2004.This regulation was relaxed in 2007 to allow the slaughter of any animal that collapses after an initial veterinary inspection, as long as it is re-examined and slaughtered separately.The Humane Society of the United States has sued the FDA to close this loophole, and Sen. Herb Kohl of Wisconsin, chair of the Senate Appropriations Subcommittee has also called for a complete ban on downer cows from the food supply. In addition, Kohl has called for stiffer penalties for companies that violate the ban, and for the installation of 24-hour surveillance cameras at meat processing plants.The recent controversy over downed cows erupted after an undercover Humane Society employee videotaped workers at a Westland/Hallmark slaughterhouse hosing, shocking, dragging and even using forklifts to move downed cows into the kill area."These images exposed wholly unacceptable gaps in American meat inspection systems," Kohl said. "Despite the presence of five inspectors at the Westland/Hallmark plant, blatant violations had evidently occurred for some time ... I think we need a more foolproof system."Testifying before the appropriations subcommittee, Schafer said that he believes current rules on downed cows to be adequate."I do believe there are cases where downer animals can be approved by the veterinarian and put into the food supply," Schafer said. "They are not sick."According to USDA documents, cows with broken limbs, even those that appear otherwise healthy, are 50 times more likely to have mad cow disease than animals that can stand on their own.