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Maranda Christensen
Professor Dursema
English 1010
20 Apr 2015
The Sub-therapeutic Use of Antibiotics in Livestock
In 1945, Alexander Fleming accepted a Nobel Prize for the discovery of penicillin, he
warned that the under dosing of this drug may make microbes resistant. These same drugs
(antibiotics) are being used sub-therapeutically for livestock in factory-like facilities all
over the United States (U.S.). The
practice of giving antibiotics to farm
animals to promote quicker growth
or prevent disease (subfoodandwaterwatch.org
therapeutically) is creating resistant bacteria that can be spread by human consumption of
these factory raised animals.
Reports from the Food and Drug Administration (FDA), 32.6 million pounds of
antibiotics were sold domestically for animal use in 2013. This accounts for 80% of all
antibiotic sales in the U.S: Of this only
60% were considered medically
important. The additional 40% of
“Giving antibiotics to animals routinely is like
giving antibiotics to your kids before they
head off for daycare when what they really
should be doing is washing their hands.”
Avinash Kar, Natural Resources Defense Council senior
attorney
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antibiotics are being used for sub-therapeutic purposes which is creating super-bugs in our
livestock and their feces.
According to the Centers for Disease Control and Prevention (CDCP), antibioticresistant bacteria are responsible for some two million illnesses annually in the U.S., and
more than 23, 000 deaths. Although it is unknown how many of these illnesses were from
the consumption of antibiotic fed livestock.
The risks of increased microbial resistance are far more significant than the benefits
of growth promotion. Antimicrobial drug use on livestock has been associated in the
development of bacterial resistance.
These bacteria can be spread through
the slaughtering process by which
the bacteria held in the intestines and
gut are able to escape and
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contaminate the meat intended for human consumption: some of these bacteria such as,
Salmonella and Campylobacter can cause illness in people. Because these bacteria may be
resistant due to the animals’ exposure to antibiotics, it may cause food-borne illnesses in
people that is difficult to treat (Torrence, 293).
A study conducted by researchers at the Centers for Disease Control and
Prevention, published in Science in 1984, showed that antibiotic-resistant bacteria could be
transferred directly from meat to humans. This same study showed 20% to 30% of the
Salmonella outbreaks in the U.S. involved antibiotic-resistant strains. Additional evidence
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was provided by a team of researchers of Minnesota; the researchers found that after a
certain antibiotic was approved for use in livestock that 10.2% of bacteria were resistant
compared to the 1.3% that were resistant prior to the drug use approval (Chiras 519).
Consumption of the meat, however, is not the only way that these resistant bacteria
can threaten human health. Along with possible consumption through milk and eggs, these
antibiotic-resistant bacteria can be transmitted via air. This is because the antibiotics used
for growth promotion are added to livestock feed, and are poorly absorbed in the
gastrointestinal tract through the digestion process resulting in excretion of parent
compounds and metabolites
(McEachran et al. 3). These
compounds may be transported
into the environment beyond feed
yard boundaries through manure
Figure 1 Showing dust from a Factory Farm; this dust could be carrying
antibiotic-resistant bacteria, courtesy of gmoinside.org
waste and become airborne.
Specifically in Texas, Oklahoma, Kansas, Nebraska and Colorado where 76.3% of all cattle
reside, due to the higher frequency of dust storms (McEachran et al).
A new study conducted in 2014 by Texas Tech researchers showed that
Tetracycline, an antibiotic used for growth promotion in livestock, turned up in 60 percent
of samples collected downwind and 30 percent of the upwind samples. This study was
conducted in the fall and winter months, when temperatures are mild and wind is moderate.
These samples were collected with portable air samplers placed 10-30 yards upwind and
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downwind of feedlots. It is unknown if the level of antibiotics and antibiotic-resistant
bacteria transferred via air is high enough to affect humans. These traces of antibiotics and
bacteria are also contaminating surrounding soil surfaces, water surfaces, vegetation, and
other living organisms. Note that the above study was conducted in the calmer months of
the year, the amount of contamination may be higher in the months where winds are high
and soils are drier.
Factory farms raise livestock with disrespect, the “benefit” of growth by using
antibiotics sub-therapeutically is causing
these animals to gain weight much more
rapidly which forces them to live in very
close proximities. Livestock are basically
living in one another’s feces and there is
no need for a study to prove that this
causes higher risk for the spread of
Figure 2 showing the close proximities that livestock are
forced to live in, courtesy of awfw.org
bacteria (disease).
There are many ways that traces of these antibiotic-resistant bacteria and the
antibiotics themselves can be ingested and effect humans. Continuing to feed and
administer antibiotics on sub-therapeutic levels to livestock may create detrimental effects
on human health. The risk of contracting an illness that is untreatable far outweighs the
benefits of raising livestock at a quicker rate. Not only is this putting human health at risk,
it is disrespecting food animals to the point that these livestock are forced to live in close
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proximities and at times gain so much weight that they are unable to move. This leaves a
greater chance for the spread of disease from animal to animal, through the feces and other
matters and thus, possibly transferred to humans through the consumption of these
livestock.
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Works Cited
Chiras, Daniel D. “Evolution and Ecology.” Human Biology. Burlington: Jones & Barlett
Learning, 2015. 518-519. Print.
Kessler, David. “Antibiotics and the Meat We Eat.” Nytims.com. The New York Times
Company, 27 Mar, 2013. Web. 8 April 2015.
McEachran, Andrew D., Brett R. Blackwell, J. Delton Hanson, Kimberly J. Wooten,
Gregory D. Mayer, Stephen B. Cox, and Philip N. Smith. “Antibiotic Resistance
from Cattle Feedyards.” 3. Web. 14 April. 2015.
National Research Council. The Use of Drugs in Food Animals: Benefits and Risks.
Washington, DC: The National Academics Press, 1999. Print.
Torrence, E. Mary and Richard E. Isaacson. Microbial Food Safety in Animal Agriculture.
Iowa: Iowa State Press, 2008. Print.