February 6, 2004. New York Times. By DENISE GRADY
In the month and a half since a case of mad cow disease was discovered in Washington State, Americans have been learning more than they wanted to know about what cattle in this country have been eating.
Though consumers may imagine bucolic scenes of nursing calves and cows munching on grass or hay, much of American agriculture no longer works that way. For years, calves have been fed cow's blood instead of milk, and cattle feed has been allowed to contain composted wastes from chicken coops, including feathers, spilled feed and even feces.
Most people had never heard of those practices until last week, when the Food and Drug Administration barred them, saying they could spread mad cow disease. But the agency did not prohibit other practices that involve using animal remains to make cattle feed.
Though the United States banned the use of cow parts in cattle feed in the 1990's, it still permits rendered matter from cows to be fed to pigs and chickens, and rendered pigs and chickens to be fed back to cows. Critics say that in theory, that sequence could bring mad cow disease full circle, back to cows.
On Wednesday, an expert panel advising the government urged a ban on using any animal remains to make feed supplements for cattle. The European Union has such a rule, but America does not, and the cattle industry has accused the advisory group of exaggerating the risk in this country.
Europe barred animal parts from cattle feed because scientists suspect that tissue from infected animals, particularly the brain or spinal cord from sick cows, can transmit the disease. Contaminated feed is widely believed to have started the mad cow epidemic that infected more than 180,000 animals in Britain in the 1980's and has led to the death of more than 140 people.
Any decision by the United States to take the panel's advice, barring all animal protein from cattle feed, could have a large effect on another low-profile part of the livestock industry: rendering - that is, pressure cooking on an industrial scale. Protein supplements derived from rendered livestock are added to feed to help animals gain weight and produce more milk.
Decisions about what kinds of rendered animal parts can go into cattle feed are made by the Food and Drug Administration. Dr. Stephen Sundlof, director of the agency's Center for Veterinary Medicine, said there was no evidence that pigs or chickens could transmit mad cow disease. He said the F.D.A. needed to study the expert panel's report further to determine whether the feed rules should be made stricter. He noted that the new report had come to conclusions very different from those in a 2001 report by Harvard researchers that the agency has relied on to make its rules.
When the new report was issued, "I asked the committee, `Help me here, as a regulator who has to base their decisions on science, and now I'm confronted with two very different scientific opinions,' " Dr. Sundlof said. "We need to find out what is at the root of that," he added, "before we can make any decisions different from what we made last week."
Dr. Gary Weber, executive director for regulatory affairs at the National Cattlemen's Beef Association, said the cattle industry was prepared to change feeding practices if the F.D.A. determined that doing so was necessary. Dr. Weber said he did not know what percentage of cattle in this country are fed animal protein supplements. "On the beef cattle side, the need for animal protein byproducts has never been high," he said. "But in the dairy industry, in order to sustain high levels of milk production, they have needed these proteins and felt it was important in high-producing dairy cows." Dairy producers can switch to soy protein, but it does not work as well, Dr. Weber said.
Tom Cook, president of the National Renderers Association, based in Alexandria, Va., said his industry was discussing the issue with government officials and trying to determine what changes would be needed and what their impact might be. Rendering is a $3 billion industry, with about 240 plants in the United States and Canada that process about 50 billions pounds of animal remains a year.
Rendering yields fats, including tallows and greases, as well as meat and bone meal. The fats can be made into soaps and lubricants, and also added to some animal feeds. Most of the meat and bone meal are used in feed supplements for animals; 43 percent goes to poultry, 23 percent to pet food, 13 percent to swine, 10 percent to cattle and 11 percent to other uses, among them the production of feed for farmed fish.
If it was barred from animal feed, rendered material might lose its value, Mr. Cook said. And yet, he said, the remains would still have to be rendered, because that is the best way to dispose of them. "The material still has to be processed," he said. "If it doesn't get rendered and find a home, you'll have to build a lot more landfills and means of disposal not as safe or environmentally acceptable as rendering. And the cost will have to be shifted to somebody, I don't know who."