May 23, 2001
New research suggests feeding cattle diets less high in grain would solve
much of the need for antibiotics, an issue which has limited U.S. beef
Diets of starchy, high-calorie grain trigger disorders in cattle that must
be treated with antibiotics and other drugs, new research from USDA and
Cornell University suggests. In typical commercial beef production, steers
are fed a 90-100-percent grain diet for several weeks in feedlots prior to
slaughter so that tender, tasty fat marbling is added to the muscle.
According to James Russell, USDA researcher working at Cornell, an all-grain
diet is not natural to cattle. As ruminant animals, cattle are designed to
consume and digest huge quantities of high-cellulose, low-nutrition grass.
That's why they have four stomachs. "When you feed cattle 90 or 100-percent
grain, it creates an acidosis in the rumen (stomach) and the rumen wall
becomes ulcerated," he said. Bacteria migrate through the ulcers and infect
the liver, where they cause abscesses. "At least 13 percent 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. If they didn't
give antibiotics, about 75 percent of the animals' livers would be
abscessed." Cattle producers and feedlot managers give cattle antibiotics to
suppress the bacteria. Subtherapeutic doses of certain antibiotics, plus
hormones, also stimulate growth by increasing feed conversion efficiency.
However, the practice of giving cattle antibiotics and hormones has come
under attack from environmental and animal-welfare organizations, which
claim over-abundance of antibiotics in the environment leads to the
development of antibiotic-resistant pathogens causing disease in humans that
resists traditional antibiotic therapies. Imports of beef from
hormone-treated cattle was banned by the European Union in the mid-'80s.
This eliminated a valuable export market for the U.S. beef industry. Though
the industry has challenged the so-called "hormone ban" several times in
court and has won, the ban remains in place.
Russell said high-grain diets may cause other problems in cattle, such as
bloating. He estimates that approximately three of every 1,000 cattle in
feedlots die of grain-related disorders. The fatty, starchy grain causes
food to move slowly and sluggishly through a steer's digestive system,
building up high levels of acid in the rumen. About half the bicarbonate
soda produced in the United States -- a common home treatment for stomach
problems in humans -- is fed to cattle to help neutralize the acid in the
rumen. Beef producers also give cattle lime to calm their stomachs. Other
estimates suggest that more than half the antibiotics manufactured in the
United States are fed to livestock.
According to Russell, cattle are healthiest when they eat grass, hay, and
other high-fiber feeds. The high cellulose content of these feeds stimulates
the gut to work properly and limits the production of acid in the rumen.
Animals gain weight without the risk of developing liver abscesses.
However, grass and hay are low in nutrition, requiring months before cattle
gain enough weight to be commercially marketable.
Russell said he does not oppose feeding cattle grain. He is looking for
alternative ways to fatten cattle economically without causing them 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. He believes these health problems could be controlled when cattle are
given more time for grazing before they eat weight-gain-stimulating high-fat
grain diets. He also suggested changing the diet in feedlots to about 60
percent grain and 40 percent hay or grass.
Gary Weber, spokesman for the National Cattlemen's Beef Association, called
it "a challenge" to raise cattle economically. "We fully support any
research that will help us produce beef more efficiently."