Danish experience offers lessons for U.S. antibiotic use
Danish experience offers lessons for U.S. antibiotic use
by H. Scott Hurd D.V.M., Ph.D., Iowa State University and Former Deputy Undersecretary Food Safety
In 2000, due to concerns about increasing antibiotic resistance in human infections, Danish pig and poultry producers voluntarily stopped using any antibiotics for purposes of disease prevention and growth promotion. This ban became legally binding in 2000, applying to cattle as well.
It was expected that a ban on growth promotion and preventive uses would reduce total antibiotic consumption in livestock. However, as was reported by the Danish government, "consumption has increased gradually by 110 percent from 1998 through 2008."
The economic costs of the ban were great; increased costs resulted from increased days to weaning and to market, reduced feed efficiency and increased piglet death.
It does not appear the public health in Denmark has improved since the ban; Salmonella and Campylobacter illness rates have not decreased and methicillin resistant Staphylococcus aureus (MRSA) has been steadily increasing for the last 10 years. Additionally, the resistance levels in some key human infections has not declined, but increased.
Denmark has a mixed market capitalist economy, but it has a large welfare state, ranked as having the world’s highest level of income equality and taxes. Its economy is a mixture of socialism and capitalism, which is also evident in the way pigs are raised in Denmark. Data shared in this article will focus on hogs, since most of the data regarding the Danish antibiotic ban relate to pork production, a major export commodity for Denmark (85% of production is exported).
In Denmark, most pigs are produced under a very successful cooperative. The farmers essentially "own" the entire production system; the pigs, the processing plant and the retail and export business. However, most individuals still own the farm land. This cooperative structure brings about different economic incentives. Producers can absorb some additional production costs (e.g. doing without antibiotics) with hopes of recapturing that cost when selling their product at export. So when Danish producers report that, "the ban has no economic effect," they are likely expressing a different economic reality than would occur in the United States if similar production constraints were imposed.
Additionally, Denmark is a small country of 5.5 million people, only 500,000 beef cattle and 27 million pigs. Its national pork production is slightly more than that of Iowa. A comparison of "national experiences" between Denmark and the United States should be conducted carefully, as Denmark is much different from the United States.
In 2000, Denmark began a public health policy experiment that is informative for us all, especially given the excellent data on antibiotic use and antibiotic resistant bacteria available from the Danish government. Because of concerns about increasing resistance in human infections, Danish pig and poultry producers voluntarily stopped, before 2000, using any antibiotics for purposes of disease prevention and growth promotion. This ban became legally binding in 2000, applying to cattle as well.
It is important to be cautious about using national data for making cause-and-effect conclusions. However, the same approach used to justify the Danish ban is being used in the United States. It is tempting to look at a relationship between two trends and assume they are causally related, when actually both trends may be driven by different unrelated factors. For example, the increase in U.S. gasoline prices over the last few years occurred during the same time as the popularity of the Internet increased. However, it would be inappropriate to say one is causing the other or both are caused by something else.
In evaluating the effect of the ban we will use the same three criteria used to justify it: It will
- reduce antibiotics used in the country (assumed to be a good thing);
- It will not harm animal health; and
- It will be good for public health.
Since the use of antibiotics in humans or animals is thought to increase risk from resistant bacteria, it was assumed that any reductions in the total quantity used would be a good result of the ban. It was expected that a ban on growth promotion and preventive uses would reduce total antibiotic consumption in livestock. However, as was reported by the Danish government, “consumption has increased gradually by 110 percent from 1998 through 2008. During the same period meat production has increased (only) 32 percent from 20.9 billion kilograms to 27.4 billion kilograms." Most of the changes were in pig production. The Animal Defined Daily Doses (i.e. the amount of antibiotic per pig) for all age groups of pigs has increased 25 percent since the ban.
Pig health was reduced
One of the main reasons for an increase in total antibiotics used was the increased amount of pig treatment required (Figure 1). The amount of antibiotics used for treatment per pig has more than doubled since 2000. Many of these drug types are more similar to important human antibiotics. As noted in the 2008 Danmap report, "the use of 3rd and 4th generation cephalosporins in pigs has been increasing significantly from 2001 to 2007 (by 374%)," As the old saying goes, "an ounce of prevention is worth a pound of cure".
In addition, if pigs and producers do not need growth promoting and preventative antibiotics, then the economic impacts should be minimal. They were not. Economists in the United States have estimated those same changes would cost U.S. producers about $4 to $6 per pig sold (Figure 2). These greater costs came from increased days to weaning and to market, reduced feed efficiency and increased piglet death. Figure 2 shows how the increased costs reduced net profit, and how pork producers would likely adapt.
Impact on public health?
The main motivators in restrictive antibiotic use policies is public health. Many concerns are mentioned when describing the "risk" of antibiotic use, such as the number of foodborne illnesses, the resistance rates in human infections and the prevalence of methicillin resistant Staphylococcus aureus (MRSA). There may be many other reasons, but it does not appear the public health in Denmark has improved since the ban. Salmonella and Campylobacter illness rates have not decreased and MRSA has been steadily increasing for the last 10 years.
Additionally, the resistance levels in some key human infections have not declined, but have actually increased. For example, according to the DanMap 2008 report, "a significant increasing trend in occurrence of resistance to tetracycline, ampicillin and sulfonamide was observed 2001-2008 both from domestically acquired human cases of Salmonella typhimurium and from pigs." Some have attributed these increased resistance rates to the shift from prevention to treatment of pig diseases.
Antibiotic use has not decreased
If there has been a benefit to the 10- year ban on growth promoting and disease preventing antibiotics in Denmark, it is not immediately obvious. Pig production is more costly, antibiotic use has increased, and antibiotic resistance and illness in humans has not decreased. Every bacterial-antibiotic-use combination presents different potential risks. Currently, the U.S. Food and Drug Administration evaluates risk of individual antibiotics within the context of their actual use. This approach is greatly preferred to broad-based bans predicated on intended uses.
J.E. Hobbs, W.A. Kerr, K.K. Klein 1998. Creating international competitiveness through supply chain management: Danish pork
Supply Chain Management: An International Journal 3: 2, pp 68 - 78
DanMap 2008. Use of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, foods and humans in Denmark. ISSN 1600-2032
Technology choice and the economic effects of a ban on the use of antimicrobial feed additives in swine rations Dermot J. Hayes, Helen H. Jensen *, Jay Fabiosa. Food Control 13 (2002) 97–101
Tags: Beef Issues Quarterly, Issues Updates, Spring 2010
June 30, 2010