Antiobiotic Use in Agriculture

A veterinarian's perspective on the issue: (link)

By Alyn M. McClure, DVM with Herd Health Management, LP

Recently, CBS News producers created a special report on the use of antibiotics in livestock production. The piece, reported by Evening News anchor Katie Couric, is not a factual representation of the scientific, safe and careful use of antibiotics in animal agriculture.

My lifetime of experience in animal agriculture makes their report seem to me biased and misleading. My parents who migrated from family farms in Oregon raised us in a small Southern California community with chickens and rabbits for meat and eggs. I worked my way through high school and college on farms and fruit orchards, a 12,000 head beef feedlot, and a university owned dairy and milk processing plant. Professionally I have worked for 36 years with dairies, feedlots, cattle and sheep ranchers in 12 states in the U.S. and in Mexico.

Without exception I have found these owners and managers to be very concerned about the ethical treatment and welfare of their animals including the responsible use of antibiotics. They have been interested in scientific and applied research, and have worked diligently to improve every aspect of herd health and implement management programs to prevent disease and minimize the need for the use of antibiotics.

Last week I was leaning against a fence post on a third-generation family dairy farm in Arizona pondering how I might respond to the CBS report since I’d gotten word they’d be airing a story on the subject. While I was reflecting, I was watching cows returning from the milking parlor playfully loping back to their pen and rapidly placing their heads side by side through the self-locking stanchions to eat. They were voraciously consuming a well-balanced total mixed ration of locally grown forages, processed grains and agricultural by-products. They had just been calmly milked by caring professional milkers using state-of-the art milking equipment. These cows walk to and from their pen twice a day on dry, padded concrete walkways to be milked. They are bedded on clean, dry and comfortable bedding in open dry lots and under shades that protect them from the elements in the winter and cool them with water spray and fans in the summer. This family has implemented many technologies to now efficiently and humanely manage thousands of milk cows better than when they started with 40 cows years ago. These cows have never been fed antibiotics, and are only treated with antibiotics when needed to cure or prevent a bacterial infection to prevent pain, suffering and death, to enable these cows to achieve their potential to feed us and a starving world with safe, wholesome, and affordable food. That is how less than 1% of the U.S. population is involved in agriculture and can provide for the other 99% and have surplus to export to developing nations.

How are antibiotics used in animal agriculture? Besides treatment of an individual sick animal, after every possible effort has been made to successfully manage genetics, housing, environment, nutrition, feeding, vaccination and other herd or flock health practices, antibiotics may be used in feed or water to treat, control or prevent disease and to promote growth and feed efficiency. This use has been proven to improve animal health and welfare (less disease and mortality), improve growth and feed conversion (reduces bad bacteria; promotes good bacteria), and improve food safety.

I welcome open dialogue and evaluation of our agricultural production practices. It can only make us better. I do ask the evaluation to be scientific and objective, and the reporting to avoid sensationalism, hyperbole, and misleading statements aimed at inflaming opinion. The CBS News report is extremely critical of the use of antibiotics in agriculture, repeating the oft-stated but unsupported assertion that there is an alarming rise in the incidence of antibiotic resistant bacteria among farm animals. I have not recognized this as a problem in 36 years of dairy practice. Surveillance data regarding bacterial isolates from cattle by the National Antimicrobial Resistance Monitoring System does not support their claim either.

Opponents of antibiotic use in food animals claim that we don’t need antibacterials to produce meat and eggs, that their use has lead to a significant increase in antibiotic resistant bacterial infections in humans, and that their use reduces the effectiveness of human medicines. In 1999, the Heidelberg Appeal Nederland Foundation, renowned for its unbiased scientific research, conducted a study on the effect of antibiotics used for growth promotion in food animals, and concluded that there was no conclusive evidence that their use contributed to human disease or compromised the efficacy of related antibiotics in human medicine.

After growth promoting antibiotics were legislatively banned in food animals in Denmark in 1999 in an attempt to protect public health from antibiotic resistance, there has been no reduction in the incidence of antibiotic-resistant hospital isolates in humans. In some cases resistance has increased and the incidence of some types of infections in humans has also increased. Unfortunately, disease and mortality have increased among animals, producing adverse animal welfare conditions. As a result, to treat the higher incidence of disease in animals in Denmark, it has been necessary to increase the use of antibiotics for therapeutic treatment in animals. The use of antibiotics in humans has also increased. The increased health costs and labor and the reduction in growth and feed conversion in pigs have resulted in increased production costs of $5.29 per pig.

Some purport that antibacterial-free farming makes food safer. The truth is that antibiotic use in food animals makes them healthier which makes our food safer. Chickens raised without antibiotics are three times more likely to carry bacteria that can make people sick. When the EU phased out certain antibiotic uses there was no discernable improvement in food safety. Food handling and preparation has a much greater impact on food safety. In the U.S., food-borne pathogens decreased by 15 to 49% from 1996 to 2001 following the implementation of the new FSIS/HACCP (Food Safety Inspection Service/Hazard Analysis Critical Control Points) regulations. Proper food handling and cooking prevents human infection by food-borne pathogens.

Some bacteria are naturally resistant to certain antibiotics; others acquire resistance by genetic mutation over time; and some acquire resistance after exposure to an antibiotic used in human medicine or animal production. For a person to have an antibiotic treatment failure due to acquiring a foodborne bacterial disease from eating, for example, pork, the following things would have to happen:

- The antibiotic would be used in the animal

- The animal would have to develop a resistant bacterial strain

- The resistant strain would have to survive through food processing/handling

- The resistant strain would have to survive through food preparation

- The resistant strain would have to transfer to the human

- The resistant strain would have to colonize

- The resistant strain would have to cause a disease

- The antibiotic treatment would have to fail

What is the probability of a person experiencing a treatment failure due to antibiotic use in swine? Here are some risk comparisons:

Risk Comparison	Annual Probability
Being struck by lightening	1 in 550,000
Dying from a bee sting	1 in 6 million
Dying from a dog bite	1 in 18 million
Acquiring resistant campylobacter from macrolide-treated swine resulting in treatment failure	<1 in 53 million
Acquiring resistant E. faecium from macrolide-treated swine resulting in treatment failure	<1 in 21 billion

It’s easy for me to say that antibiotic resistant bacteria are not a problem when I haven’t personally experienced such an infection, but that’s meaningless to a person who has. It’s like trying to console a person who has been unable to find work for six months by informing them that the national unemployment rate is only 10%. In fact, while competing in high school athletics my daughter got a nasty skin infection on her leg caused by antibiotic resistant staphylococcal bacteria (MRSA). A few months later my wife got a lip infection caused by the same type of bacteria. These infections did not come from animal agriculture nor did the antibiotic resistance. The resistance is real but many scientists believe the primary cause is misuse (over prescribing) of antibiotics in human medicine and/or failure of patients to complete the prescribed regimen.

Antibiotic use in animal agriculture is by or on the order of a licensed veterinarian using antibiotics approved by the FDA, having passed its stringent testing requirements for efficacy and safety (for animals, our food and the environment). All major industry associations have established prudent drug usage guidelines: the American Veterinary Medical Association, American Association of Bovine Practitioners, American Association of Swine Veterinarians, American Association of Avian Pathologists, National Chicken Council, National Pork Board, National Cattlemen’s Beef Association, and others. These guidelines and FDA oversight insure that antibiotic use in food animals will protect animal health and welfare leading to production of safe, affordable and abundant food, critical to our U.S. food security.

Maintaining the health of U.S. herds and flocks requires agriculture producers and their veterinarians to have all approved safe and effective technologies, including animal health products, available to us. It would be a tragedy for misconceptions, misrepresentations or non-science based political agendas to deprive us of any valuable tools for preventing animal disease without substantial evidence of a benefit to human health.