010530 High-Calorie Cattle Feeding Studied

Washington - Feeding cattle diets of starchy, high-calorie grain produces more steak but gives the animals disorders that must be treated with antibiotics and other drugs, a researcher says.

Cattle being readied for the slaughterhouse are typically put on diets that are 90% to 100% grain. This makes them gain weight quickly and produce meat with the tasty marbling of fat so beloved by steak eaters.

The problem, said James B. Russell, a Department of Agriculture researcher at Cornell University, is that nature designed cattle to feed on grass and other high fiber foods. An all grain diet makes them sick, he said in a study appearing Friday in the journal Science.

“When you feed cattle 90 or 100% grain, it creates an acidosis in the ruman (stomach) and the ruman wall becomes ulcerated,” said Russell.

Bacteria, such as Fusobacterium necrophorum, migrate through the ulcers and end up in the liver where they cause abscesses.

“At least 13% of the animals in feedlots have liver abscesses, some as big as your thumb, which means the livers have to be discarded as unfit for human consumption,” he said.

To limit this problem, feedlot operators give the animals antibiotics to suppress F. necorphorum and other bacteria.

“If they didn't give antibiotics, about 75% of the animals' livers would be abscessed,” said Russell.

Usually, the antibiotics are removed the cattle diet before slaughter so the meat is not affected. However, widespread use of the drugs can cause the development of antibiotic-resistant bacteria, he said.

High grain diets cause other problems, such as bloating and liver failure, and Russell estimated that about three out of every 1,000 cattle in a feedlot die of grain-related disorders.

High levels of grain in the cattle diet, said Russell, cause a slow and sluggish movement of food through the animal. This allows the starchy grain to build up high levels of acid in the ruman and the acid causes the ulcers.

The researcher said that about half of the bicarbonate of soda produced in the U.S. is fed to cattle to partially neutralize the acid from high grain diets. The industry also use lime placed in the animal feed.

Russell said that cattle are healthiest when they are fed diets that include grass, hay or other high fiber matter. This prompts the animal's gut to work properly, limits the production of acid and allows the animals to gain weight without the need for antibiotics against liver abscesses.

But grass and hay are low in nutrition, compared to grain, and it takes months longer for cattle to reach market weight, said Russell.

The researcher emphasized that he was not advocating that cattle not be fed grain, but, instead, is looking for ways to fatten cattle economically without causing the health problems.

“If we switched all the cattle from grain to hay, the supply of hay in the United States would not be enough to make up for the deficit,” he said.

Instead, Russell said the problem could be controlled by allowing the cattle to spend more time grazing and eating hay before they are put on the fast-weight-gain diet of grain. Another technique, he said, would be for the cattle to be fed about 60% grain and about 40% hay or other high fiber foods. This would slow the fattening process, however.

Gary Weber of the National Cattleman's Beef Association acknowledged that “it is a challenge” to raise cattle economically since it requires a balance between quickly fattening the animals for slaughter and keeping them properly fed and healthy at the same time.

He said Russell is known for his research efforts and “we fully support any research that will help us produce beef more efficiently.”

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