BOONE, Iowa — hing his Black Angus steers shove one another toward two long troughs, rancher Marshall King knows that his livelihood and the health of the U.S. beef industry depend on the safety of the coarse yellow feed doled out to cattle like his across the nation.
Mad cow disease--a brain-wasting illness believed to be spread through feed containing infected cattle products in Europe--has not appeared in the United States. Federal regulators have devised layers of protection to keep it out, or to contain a possible outbreak.
But the feed production and distribution system is vulnerable at many points, regulators say.
Millions of tons of cattle feed are processed at thousands of mills across the country. Along the way from field to feeding trough, the ingredients make several stops, crossing paths with ingredients intended for other feeds. At every step, there is the danger that they could be tainted by cattle products, which are allowed in feeds meant for other animals, such as hogs.
At the feedlot, ranchers do their own final mixing, combining corn, hay, soybeans and other additives.
Stringent federal guidelines are designed to ensure that feed is handled safely at every step, but a shortage of inspectors means many producers are never checked. There is no routine screening of feed for contaminants.
If a cow shows symptoms similar to mad cow, its brain is sent to a U.S. Department of Agriculture laboratory in Ames, Iowa, for examination.
"The system is so fragile," said Larry Blunt, head of the feed division for the Iowa Department of Agriculture. Blunt is confident his state's mills have been vigilant--all have been inspected--but admits, "Human error could happen anywhere at any time."
The system's weakness was exposed last week, when Purina Mills Inc. admitted that a herd of roughly 1,200 cows in Texas received feed containing traces of cattle meat and bone meal.
The news set off alarm among U.S. beef producers--especially in Iowa, America's largest feed-producing state--who fear that consumer hysteria, if not the disease itself, could cripple the beef industry.
That was evident last week, when cattle futures dipped amid news that candy marketed by a Chicago company contained gelatin derived from European cattle. And this week, a Maryland physician questioned whether consumers can be sure that herbal supplements--many of which contain animal parts--are safe.
In Europe, where mad cow has killed thousands of head of livestock and has been linked to at least 83 human deaths, the disease is thought to have spread by cattle eating feed containing meat and bone meal of diseased cows.
Allowing meat products into cattle feed would not pose a danger in itself as long as mad cow remains overseas. But if America falls prey to the disease, it could spread through the feed chain of the Midwest.
Since 1989 the FDA has raised an escalating series of barriers to any importation of European beef products. As an additional precaution, U.S. regulators in 1997 banned the use in cattle feed of any meat and bone meal from animals susceptible to brain-wasting illnesses--cows, sheep, goats, deer and elk. Cattle protein can be used in hog, horse and poultry feed, however.
Iowa alone produces mountains of feed, 16 million tons annually. The most common ingredients--corn and soybeans--are grown in the state. After harvesting, much of the grain is sent by trucks to processors who mill it and then distribute it to ranchers.
In a second process, a protein source, usually a hog byproduct such as bone meal, is added with vitamins and minerals to the cattle feed.
At King's ranch in central Iowa, snowdrift-size piles of hay, gluten, soybean and corn products sit next to a grain silo that holds a mixture of vitamins and protein.
Twice daily, King or his son Jon drives a flatbed mixing truck that melds the ingredients and then distributes the feed into troughs several blocks long.
Of the 25 pounds a day each one of King's steers consumes, less than half a pound constitutes a protein supplement, usually including a small amount of hog byproducts, he said.
King, 70, trusts that the protein is free of cattle products because he trusts the integrity of the grain mills and distributors.
"These are people I have been dealing with for years," said King, who has been fattening cattle here for half a century. "I know they want to do things right."
But there aren't enough people checking to be sure things are done right. In Iowa, it took a half a dozen state inspectors nearly three years to crisscross the state and visit more than 750 producers and distributors.
A survey released last month by the U.S. Food and Drug Administration found that hundreds of producers in the last three years have violated federal regulations.
In the survey, involving 1,593 mills, nearly 50 percent lacked proper warning labels and 26 percent had no systems to prevent accidental mixing of meat and bone meal into cattle feed.