WASHINGTON — In a significant reversal, major meat and dairy industry groups on Tuesday backed a total ban on so-called downer cattle from entering the food supply.

Calls for such a ban have come from watchdog groups and some lawmakers in the wake of the massive beef recall from a Southern California slaughterhouse in February, but industry had resisted.

Current law bans slaughter of most cows that are unable to stand, but they’re allowed in if they fall down after passing a veterinarian’s inspection and then are re-inspected.

Advocacy groups called that a loophole, but the Agriculture Department and the meat industry opposed changing it.

Now, under pressure from Congress and outside groups, the industry has reconsidered.

The American Meat Institute, the National Meat Association and the National Milk Producers Federation announced Tuesday that they have petitioned the Agriculture Department to enact a total ban.

“We think that the time has come,” said Jeremy Russell, spokesman for the National Meat Association, which is based in Oakland, Calif., and represents some 400 packers and processors. “We want to send a clear message to consumers that we’re putting their welfare and concerns ahead of the economics.”

A spokeswoman for the Agriculture Department’s Food Safety and Inspection Service did not immediately respond to messages seeking comment. Agriculture Secretary Edward Schafer said in the wake of the recall that he thought the existing rule protected food safety, and that it was not fair to cattle owners to ban the slaughter of cows that may be perfectly safe to eat and just have a broken leg or hip.

Schafer wasn’t able to estimate how many additional cattle might be affected by a total ban, and the overall economic impact is difficult to calculate, though Mark Dopp of the American Meat Institute said it wasn’t expected to be significant. Dairy farmers get several hundred dollars for each cow they sell for slaughter.

Undercover video taken at the Westland/Hallmark Meat Co. in Chino, Calif., showed workers shocking cattle and pushing them with forklifts to force them to slaughter. That led to the recall of 143 million pounds of beef, though authorities said the health risks were minimal.

Downer cows are more prone to infections such as mad cow disease partly because they typically wallow in feces.

The Humane Society of the United States has sued to enforce a complete ban on downers, and some in Congress have supported legislation to accomplish the same thing.