Although no definitive data are available, the Union
of Concerned Scientists estimates that 70% of antibiotics
in the U.S. are fed to pigs, poultry and cattle –
not to treat illness, but rather to promote slightly faster
growth and to compensate for crowded, stressful, and unsanitary
conditions. Recent studies, including one by the World
Health Organization, show that ending the routine
feeding of antibiotics to livestock and poultry can dramatically
reduce the levels of resistant bacteria present in those
animals.
Why Use Antibiotics In Feed?
Antibiotics have been put into animal feed since 1946, when
experiments showed low levels of antibiotics could help
food animals grow faster and convert feed into weight more
efficiently. Antibiotics are used in 90% of starter feeds,
75% of grower feeds and more than half of finishing feeds
for pigs in the U.S. Despite their widespread use, no one
knows exactly how antibiotics work to promote growth in
animals.
Use of feed laced with antibiotics is both routine and common
in America's version of industrial animal agriculture. Large
confined animal feeding operations (CAFOs), which often
raise pigs, poultry or cattle by the tens of thousands under
crowded conditions, have replaced small-scale farms as the
chief producers of the nation’s beef, pork and poultry.
They depend on antibiotics in animal feed not only to promote
growth but also to compensate for crowded and often less-than-hygienic
conditions, which stress the animals and make them more
prone to infection. Unfortunately, low-level use of antibiotics
for extended periods of time is one of the best ways to
speed the development of antibiotic-resistant bacteria.
Human Antibiotics Commonly Used
The same mechanisms by
which bacteria in humans develop resistance also work in
animals that are fed antibiotics. The genes that confer
antibiotic resistance to bacteria can travel from food animals
to humans via several routes, including on contaminated
food and through contamination of
the environment.
Many of the antibiotics routinely given to healthy livestock
and poultry to promote growth are identical, or nearly so,
to drugs that health providers rely on to treat sick humans.
These include penicillin, tetracyclines, erythromycins and
bacitracin, among others. For example, the Union of Concerned
Scientists estimates that nearly 5 million pounds of two
tetracycline antibiotics are fed to swine each year in the
U.S. The volume of these two medicines fed to pigs alone,
according to UCS estimates, is sixty percent greater than
the volume of all antibiotics given to sick humans.
Alternatives to Antibiotics Available
Europe is moving
in the direction of a total ban on routine use of antibiotics
in animal feeds. Sweden and Denmark have already completed
a phaseout, while other European Union countries have ended
such uses of most antibiotics and are scheduled to end use
of the rest by 2006. These nations have led the development
of large-scale livestock management techniques that use
better hygiene rather than antibiotics to raise healthy
animals, with no interruption in the meat supply. A growing
roster of
U.S. producers also avoids routine use of antibiotics.
Back to Top
last updated 12/4/03
