About antibiotics and livestock production

What does factory farming have to do with the diminishing effectiveness of antibiotics? A lot more than you might think...

Increasing antimicrobial resistance is presenting challenges to caregivers trying to rid resistant ‘superbugs’ such as c. difficile from hospitals and other care facilities across the country. Some experts suggest over prescription of antibiotics in treating human illness is contributing to the problem, but another potential source of resistance is the overuse of antibiotics by factory farming operations.

The last few decades gave rise to a dramatic increase in the quantities of drugs used annually in veterinary medicine and animal husbandry. Many of these antibiotics are the same as those used to treat human illness, and the increase in use for animals is mainly due to the routine employment of antibiotics for growth promotion – primarily by intensive livestock operations.

Regular subtherapeutic (drugs administered for reasons other than the treatment of illness) doses of antibiotics can accelerate growth in some farm animal species, and in North America antibiotics are incorporated into commercial animal feed for this purpose.

Subtherapeutic use of antibiotics has become commonplace among livestock producers because overcrowded conditions are the norm at most modern operations. Concentrated animal feeding operation (CAFO) conditions account for the vast majority of the antibiotics and related drugs used in the United States. The proportion of subtherapeutic use in industrial livestock in Canada is likely as high, but exact Canadian statistics are not available because of the “own use” provision, allowing veterinary drugs to be imported in quantities that are not subject to any reporting. The drugs are delivered to animals under conditions conducive to the development of resistance. Chicken houses, for example, can contain 50,000 birds or more. And the US Environmental Protection Agency estimates there are about 11,000 operations with over 1,000 beef cattle, 700 dairy cattle, 2,500 hogs, or 30,000–125,000 chickens south of the border.

Antibiotics used as growth promoters perform best when conditions are worst, such as in crowded cattle feedlots. It has been shown in both Sweden and Denmark that if there is less overcrowding and infection control techniques are implemented, the economic advantages of using growth promoters may be eliminated.

A major problem with the overuse of antibiotics is the emergence of strains of bacterial pathogens that are resistant to them, reducing their effectiveness in the treatment of human illness. The constant exposure to antibiotics in quantities too low to kill all the bacteria results in weaker strains being eliminated and more resistant strains going on to reproduce. Eventually the population of microbes evolves to be highly resistant, rendering the antibiotic ineffective. Bacteria are also very adept at exchanging genetic information, so antibiotic resistance in bacteria found in livestock production can be transferred to other pathogens. When antibiotics then are used to combat human illness, bacterial resistance can render such treatment ineffective, and previously easy-to-treat illnesses can become serious and even life-threatening.

The medical community in Canada has already adopted measures to curb the over prescription of antibiotics in treating human illness. Isn’t it time to think about similar reductions on factory farms?

To learn more about antibiotic use and factory farms please follow this link.