Currently, most downer cattle are banned from slaughter, but USDA rules allow some animals to go through if they have passed inspection earlier. Packers are required to alert USDA veterinarians in those cases so the cattle can be reinspected before they are slaughtered for food.

"This action sends a clear message to consumers in both domestic and international markets that we will continue to uphold the high standards to protect our food supply," Agriculture Secretary Ed Schafer told reporters.

The Humane Society of the United States, consumer groups and Democratic lawmakers in Congress have asked for the "loophole" in the downer ban to be closed. Last month, three major US meat industry groups also endorsed a total ban.

"A strictly enforceable downer ban will eliminate confusion and move the ball forward on food safety and humane standards, while restoring consumer faith in a vital American sector," said Sen. Herb Kohl, a Wisconsin Democrat.

The recommendation for a blanket ban on downer cattle came after a 60-day review, started by USDA on Feb. 28, of how meat plants operate and treat cattle.

More changes could be on the way, Schafer said. USDA's Inspector General Phyllis Fong is working on a separate investigation into the humane treatments of animals at slaughter plants and USDA is still analyzing the results from its 60-day review.

The review by the USDA came after the largest meat recall in US history occurred in February. The Humane Society of the United States released a videotape that showed workers forcing sick and injured cattle into a slaughterhouse.

Some 143 million lbs of meat, mostly beef from Hallmark/Westland Meat Packing Co in Chino, California, was recalled after the tape raised allegations the plant did not follow rules on downer cattle to get a new USDA inspection.

"This is long-anticipated but welcomed news," said Wayne Pacelle, president of the Humane Society. "For too long, sick and crippled animals have been allowed into the food supply, putting consumers at risk and subjecting injured or sick animals to needless torment."

Restrictions on downer cattle were adopted in early 2004 after the first case of US mad cow disease sparked Japan, Korea and other countries to ban US beef imports. Downer animals are at a greater risk for carrying mad cow disease and spreading foodborne illnesses.

Schafer said banning these animals from being slaughtered "will build greater public confidence" in the USDA's food safety inspection system.

He also added the ban "will reduce the likelihood that those animals will be subjected to inhumane treatment at slaughtering plants" because there will no longer be an incentive to try to get them slaughtered.

The proposed change would affect a small number of cattle. Last year, about 2,700 of the 34 million cattle slaughtered were reinspected under this exception. Just under 1,000 of these were approved and allowed to enter the food supply.