May 10, 2001
Healthier cattle feed benefits animals and people
By Amy Norton
NEW YORK, May 10 (Reuters Health) - The grain-based feed given to cattle in the US may help produce a nice cut of beef, but such feeding practices come with a price--including, researchers warn, an increased risk of exposing meat eaters to Escherichia coli (E. coli) bacteria.
Much attention has gone to cattle-feeding practices in the UK, since the country's past use of animal remains in cattle feed is believed to have triggered the spread of "mad cow" disease. Now it seems that the grain feed used in the US may have its own--albeit less severe--problems, according to a report in the May 11th issue of Science.
Grain feeds are starchy and low in fiber, a fact that makes them hard on cows' stomachs and makes it easier for E. coli bacteria to thrive in the animals. While E. coli infestation does not harm cattle, people who eat meat contaminated with the E. coli 0157:H7 strain can develop potentially deadly infections.
In a review of the consequences of grain-based feeds, researchers at Cornell University and the US Department of Agriculture in Ithaca, New York, note there is growing evidence that replacing some of the grain with fiber would be more healthful for cattle and the people who eat them.
Cattle are meant to consume fiber-rich products like hay, James B. Russell explained in an interview with Reuters Health. Starchy, low-fiber grains spur rapid growth in the animals and produce "nicely marbled" beef. But they also trigger digestive problems in cattle that can cause liver abnormalities and allow bacteria to proliferate, according to Russell.
US feedlots, Russell said, use feeds that are up to 90% grain because cattle grow about three times faster on such a diet as they would on hay. Yet, because grain-based diets can make the animals sick, grain feeds must contain additives such as antibiotics. This practice is of growing concern because scientists put part of the blame for the emergence of treatment-resistant infections in humans on the widespread use of antibiotics in food animals.
However, Russell said, if more fiber were added to the diets of cattle, feedlots might be able to cut their antibiotic use.
"But the feedlot industry doesn't like hay," he noted. "One reason is that it's hard to handle."
However, Russell pointed out, researchers are finding that an easier-to-handle source of fiber may lie in the "leftovers" that remain in the process of making beer and other alcohol. "Distillers' grains," he explained, are much less starchy and higher in fiber than traditional cattle feed is. Yet it handles like current grain feeds, and there is evidence that cattle grow nearly as fast on it.
"Further research is needed," Russell said, "but preliminary data from the University of Nebraska suggest this is a viable option."
Besides animal and human health concerns, adding more fiber to cattle's diets makes sense because the animals simply like it, Russell noted. "From personal experience, I know they would like to have some," he said. "They know it's good for them."
SOURCE: Science 2001;292:1119-1122.