Undercover video shows sickened cows, too weak to walk, being jabbed with forklift blades, kicked, shocked and even sprayed in the face with powerful jets of water by workers at the Hallmark Meat Packing Company in Chino, California.

"The attempt was to make them so distressed, to cause them so much suffering that these animals would get up and walk into the slaughterhouse," Humane Society President Wayne Pacelle told CBS News consumer safety correspondent Nancy Cordes.

The plant supplies Westland Meat Company, which is a major provider of meat to the USDA's school lunch program.

Wednesday, Westland's president and CEO temporarily suspended operations at the plant saying, "We are shocked, saddened and sickened by what we have seen."

"Downer cows" - those unable to walk because of illness or injury - are restricted from use in school lunches and elsewhere.

Cordes reports that meat-industry officials say there is no way to know if the cows actually entered the meat supply. They point out that the clearly ailing livestock would have had to pass a gauntlet of USDA veterinarians and inspectors before being slaughtered and sent to market.

Nevertheless, the USDA today stopped Westland from supplying meat to federal food and nutrition programs pending the outcome of its investigation.

And while the workers in this video have been fired, the Humane Society says the most shocking thing about the abuse shown here is that it happens all the time.