Why are antibiotics given to farm animals?

I find myself saving links to articles that I have read or tearing out articles from magazines so that I can share them on the blog. Here is one article that I have had to post for almost a year now. I get asked about 20 times (or more) on Farmer's Market days is we use antibiotics or hormones on our animals. My response is of course no. But here is a little more insight on antibiotic use.

This question was in the June/July 2009 issue of Organic Gardening.

Why are antibiotics given to farm animals?

Doug Gurain-Sherman, Ph.D., senior scientist at the Union of Concerned Scientist, replies:

Animals raised in CAFO's (confined animal feeding operations) are given human antibiotics in their feed to accelerate growth and prevent diseases caused by overcrowded and unsanitary living conditions. An estimated 70 percent of antibiotics produced in this country- nearly 25 million pounds per year- are used in animal agriculture for these nontherapeutic purposes. That's more than eight times the amount of drugs used to treat human illness.

Many physicians and scientist believe that the overuse of antibiotics in both human and veterinary medicine is contributing to the rise of antibiotic-resistant infections in humans that are costly and difficult to treat. Certain microbes that can cause foodborne illness exist naturally on livestock, and therefore proper sanitary preparation and storage of meat products is important regardless of the way the animals are raised. Because organic production does not depend on the routine use of antibiotics, however, it is much less likely to contribute to the rising problem of antibiotic-resistant foodborne pathogens.