June 2012
From the State Vet's Office

Animal Agriculture Pharmacology 101…Sort of

The debate concerning antibiotic use in food animals has been going on for a long time and a reasonable guess would be we are not close to resolving the issue. At the center of the debate is the question of the role antibiotic use in animals play in bacteria developing resistance to certain antibiotics. On one side of the debate are the folks who believe there is never an occasion when antibiotics should be used in animals that will someday end up in the human food chain. On the other side of the issue are those who believe antibiotics have a necessary role in production agriculture. I believe the use of antibiotics has a necessary place in food animal medicine if we are going to continue to meet the increasing need for animal protein as highly-populated countries like China and India continue to improve their standard of living as well as to continue to feed ourselves in the United States. Another point is that we humans may be far more involved in contributing to antibiotic resistance than using antibiotics in food animals.

Antibiotic resistance is certainly something we should all be concerned about, especially when we consider the use of antibiotics is one of a few factors credited with increasing human-life expectancy. The acceptable theory of bacteria developing resistance to certain antibiotics is when disease-causing bacteria are exposed to antibiotics — penicillin, for example — the surviving bacteria develop a resistance to the antibiotic rendering that antibiotic ineffective in treating that particular disease.

I suppose, over the years, I have seen the evening news on a handful of occasions report there is a link between using antibiotics in food animals and the rise in antibiotic-resistant bacteria affecting humans. Improper use of antibiotics, whether in humans or animals, can contribute to bacterial resistance. In the past, when a person went to the doctor coughing, sneezing and blowing snot everywhere, they expected to be treated with an antibiotic — and often that is just what they got, even though their problem was likely viral in origin. Unfortunately, time rather than antibiotics may be the cure for a severe cold. In addition to using antibiotics when they were not really indicated, people often fail to take the complete round of antibiotics prescribed to them when they actually are suffering from a bacterial disease. How many of us (yes, I am including myself) have partly-empty bottles of amoxicillin or cipro or tetracycline in the medicine cabinet we forgot to finish after we began feeling better?

Today, over one-third of the antibiotics or antimicrobials used in food animals are not even used in humans. Also, one of the complaints made about antibiotic use in food animals is they are used as growth promotants in feed. Many of the antimicrobials used in feed are for the prevention of coccidiosis. And while coccidian have the ability to develop resistance to those compounds, those organisms are very species specific and the coccidia organisms affecting poultry will not cause a problem in humans.

I am certainly not saying the use of antibiotics in food animals should not be taken seriously. In fact, I believe now, more than ever before, it is imperative we practice the wise and judicious use of antibiotics in food animals. For the sake of this article, there are two kinds of antibiotics available to producers. Those are "over-the-counter" antibiotics and those available "by prescription only." Over the years, we have seen several antibiotics and other drugs move from the "over-the-counter" category to the "prescription" column. We have seen other drugs, for one reason or another, be removed from the list of those that can legally be used in animals meant for food.

Over-the-counter drugs can be purchased without a prescription at the animal health supply. A tremendous amount of time, thought and study have gone into the decision about these drugs not requiring a prescription. The status of those drugs is always subject to change if they are not used properly. For that reason, when using over-the-counter antibiotics, it is extremely critical the medication be used exactly in accordance with the label. That includes using the proper dosage for the proper amount of time, given by the directed route of administration and observing the expiration date on the container.

Prescription antibiotics and drugs, on the other hand, require a veterinarian-client-patient relationship. That doesn’t mean the veterinarian is married to your wife’s first cousin and you only see each other at the family reunion the last Saturday in July every year. It means the veterinarian has first-hand knowledge of you, your operation and the animals needing to be treated. In certain areas of the country, where rural veterinarians are scarce, the use of prescription drugs becomes a bit of a challenge. Prescription veterinary drugs all have this statement on the label, Caution: Federal law restricts the use of this drug to use by or on the order of a licensed veterinarian. One would do well to heed that warning.

There are measures taken at establishments where food animals are processed that help make sure antibiotic residues, if present, do not make it to the food chain. Animals are tested both randomly and "for cause" for drug residues. "For cause" means, if there is reason to suspect the live animal may have been treated with antibiotics, it will be tested for residues. If residues are found, we trace back to the farm of origin and initiate measures to assure the producer does not send another animal to market without observing the proper withdrawal time (the time it takes to clear any drug residue from the animal’s carcass). Drug residue cases are becoming rare as producers become educated on the importance of using drugs in accordance with the label and observing proper withdrawal times.

Presently the Food and Drug Administration is drawing up guidelines to be helpful in the judicious use of antibiotics in food animals. This is being done with the input of stakeholders like USDA, State Departments of Agriculture, producer associations and individual producers. I fully support regulations and guidelines safeguarding the public. The one thing I want to be certain about is that these guidelines and regulations are based on science and not emotion.

Occasionally, when I watch the evening news and they are discussing the use of antibiotics and hormones in food animals, you would think they were talking about using lead, arsenic or some other really toxic substance in our food supply. I can tell you, at least on a couple of occasions, antibiotics have been very beneficial to my health. There seems to be the perception out there among some consumers, and unfortunately some lawmakers, that food animal producers get up every morning, load a back pack with antibiotics and hormones, and go load their animals up with chemicals. I have no objection to someone who wants to pay extra for meat making the claim on the label that it comes from animals never exposed to antibiotics or hormones. I just want us to be able to support the side of the debate saying the judicious use of certain drugs is not harmful to humans and we cannot continue to feed the world without those tools in our toolbox. It is important for those of us on this side of the debate to become educated about these issues and to be engaged in the debate.

Dr. Tony Frazier is the State Veterinarian for Alabama.