by Tamara Scully
Depending on what livestock you raise, and how you raise it, antibiotic use for anything other than treating a disease may not even be on your radar. But antibiotics are utilized for purposes other than disease control across livestock industries to varying degrees.
In livestock production, antibiotics are utilized for more than disease treatment. They are also used to prevent existing illness from spreading through the population, as well as prophylactically, to prevent illness from arising in the population. They are also used for production purposes.
A recent report by the USDA’s Economic Research Service (ERS) concludes that restricting the use of production purpose antibiotics won’t have much of an impact on either the broiler or the hog industry. Using a market model of price, quantity and revenue, the report “Economics of Antibiotic Use in U.S. Animal Production,” by Stacy Sneeringer, Ph.D, et.al, concludes that “the overall effect on prices and quantity are going to be modest,” if antibiotics are eliminated from livestock production use purposes.
Production purpose use of antibiotics includes growth promotion and feed efficiency. By giving antibiotics to livestock when there is no emergent threat of illness, increased rates of growth can occur, allowing the farm to spend less on feed to raise an animal to market weight. Antibiotic use for production purposes also increases animal uniformity, so that most of the animals are the same size and weight, leading to processing efficiencies.
In the broiler industry, researchers found that 48 percent of producers were utilizing antibiotics strictly for treatment of disease. Another 20 percent reported using antibiotics for other uses. The remaining 32 percent were not sure if antibiotics were being used. The broiler data was taken from 2011 Agricultural Research Management Survey (ARMS) data.
In the hog industry, which is divided into nursery and finishing operations, approximately 20-25 percent of producers did not know if antibiotics were being fed. Fifty-three percent of the nursery hog producers, as well as 59 percent of the finishing hog producers, reported no antibiotic use outside of disease treatment. The remainder report use of antibiotics for reasons other than disease treatment. Hog data from the 2009 ARMS survey was examined.
The lack of knowledge about the use of antibiotics is a result of contracting in the livestock industry, Sneeringer said. When farmers are paid to raise animals, the contractor provides the feed, and the farmer may not know what is in that feed.
Impact of antibiotic use
The study looked at a three-tiered level of impact of antibiotic use: the animal level; the farm level; and the market level.
On the animal level, antibiotic use for production purposes might result in increased weight gain per unit of feed, faster growth, less illness, better reproduction and decreased mortality. Historically, in literature from the 1950s to 1980s, research indicated that the use of antibiotics for production purposes had a strong positive impact.
But since 2000, the impact of production antibiotic use has all but been eliminated. There is only a minor impact, Sneeringer said. One prevalent theory is that the impact has been drastically reduced from that seen in early decades because of changes in production practices, such as improved housing, equipment, biosecurity measures and other management practices.
“The effect of the production purpose antibiotic uses declines over time and studies,” Sneeringer said. “You have fewer bacteria in the barn” today, so eliminating use of production antibiotics does not have a large animal impact.
Farms that currently utilize production purpose antibiotics would simply change some management strategies. Providing more space per animal and decreasing stocking densities, eliminating wildlife and human carriers, and focusing on nutrition and overall health will negate any negatives seen from eliminating production use antibiotics.
Simply increasing space per animal will allow the animal to “achieve the same grounds as it would have had with growth promoting antibiotics,” Sneeringer said.
On the farm level, there may be some decrease in economies of scale, and potentially a market penalty for animals that are not all the same size and weight. Animals may need increased feed to achieve growth, and/or feed may need to be of a higher quality. While the cost of antibiotics would decrease, purchasing feed supplements — or more or better quality feed — might increase costs. The ERS study data shows that the overall impact of the farm level use of production purpose antibiotics today is a mere one-to-three percent increase in productivity.
The market effect — when all farms do not use production purpose antibiotics — depends upon the degree of change in quantity and pricing of the meat. If there is a decline in the quantity of animals on the market, the price of the meat will increase.
But revenue, which is price multiplied by quantity, “could go up or down.”
If consumers demand more meat, because they are more comfortable with a product that does not contain antibiotics, then revenue could rise. The global market demand for U.S.-produced meat could also increase. However, if the price of production were to rise too dramatically, it could have a reverse effect on the market.
“Productivity effect on the animals is key,” Sneeringer said, and today the impact is nominal. Current research data shows that “the overall effect on price and quantity are going to be modest,” she said. The market price will increase slightly and supply will not be reduced.
Sneeringer predicts that quantity of meat will not decrease significantly as producers who already do not utilize antibiotics for production purposes will simply increase the number of animals they raise. Producers who used production antibiotics would have to make management changes, but overall their revenue would only decrease by less than one percent, Sneeringer said.
They would have plenty of management strategies to utilize instead of relying on the production effect of antibiotics. Improving living conditions to decrease animal stress by better controlling optimal temperature, ventilation and humidity level, and providing increased space per animal, will be important. Increasing house hygiene by keeping litter clean and removing dead animals will be needed. High energy feed rations can be utilized to increase growth and decrease the impact of any stressors.
Providing optimized nutrition to increase immune system functioning will be one major change. It’s theorized that antibiotic use decreases the population of gut microbes, allowing the animal to capture more energy from feed, without “sharing” it with the gut microbial population. But some of those microbes are beneficial. Increasing beneficial microbial populations through enhanced nutrition could decrease the presence of detrimental microbes, and increase animal health and growth.
Eliminating the use of production use antibiotics would not significantly impact the industry, and the impact on producers currently using antibiotics for production practices would also be minimal.
“Significant portion of livestock producers do not use antibiotics for production purposes already,” Sneeringer said.
A webinar presentation on the report, as well as the report itself, can be downloaded here: www.ers.usda.gov/multimedia.aspx