Danish public health officials have embarked on a plan to reduce the use of growth-promotant antibiotics as a means of improving the health of pigs and people. But so far, the results haven't been positive.

Three U.S. swine veterinarians have observed that Denmark's ban on antibiotic growth promotants has not improved the health and welfare of its citizens — nor its pig population.

The actions could unintentionally lead to greater incidence of human food safety problems.

Trip Objectives

The trio were part of a study team that took a pork checkoff-funded trip to Denmark in early January 2005. James McKean, DVM, Iowa State University (ISU) represented the National Pork Board's Food Safety Committee. Scott Hurd, DVM, ISU, provided epidemiology expertise. Craig Rowles, DVM, owner of Elite Pork Partnership, LLP, Carroll, IA, provided a production/veterinary perspective.

The group had three goals:

  1. To look at the impact of Denmark's ban on antibiotic growth promotants (AGPs) initiated in 2000;

  2. To look at the salmonella reduction program; and

  3. To evaluate Denmark's food safety programs and the public health impacts of the AGP ban and their salmonella effort.

“I think the ramifications of the ban on pig health are demonstrable and well documented,” observes McKean. “They have not been able to find a suitable replacement for antibiotics which would bring their herd health and performance back up to where it was before the ban. In fact, I would safely say that the variation in pigs is greater today in Denmark than it was before the ban.”

Denmark began a voluntary ban on AGPs in 1999 for grow-finish hogs. This effort went well and there were few pig health problems, says McKean.

However, in 2000, three months after officials initiated the AGP ban in the nursery, postweaning diarrhea problems increased, as did outbreaks of ileitis in younger pigs, McKean says.

Treatment costs increased, mortality rates increased 21%, average daily gain and feed conversion rates worsened, and days to market increased 1.6 days, says Craig Rowles.

By their own account, the Danes calculated an increase in cost of production of about $1.40/head. Extrapolating that expense to production in the United States, it would cost $140 million, excluding non-variable costs, explains Rowles.

To cope, the Danes have ramped up management skills and increased weaning age from 21 days to 28 days. Rowles says adding a week to weaning age in his 2,500-sow operation would require 120 additional farrowing crates — a cost of $375,000. “If you depreciate that over 15 years, that's 50¢/pig produced in depreciation expense alone,” he says.

Feed changes the Danes have made include lowering crude protein, adding more complex proteins, such as fish meal, and boosting fiber. Benzoic acid, zinc and copper are the only antibiotic alternatives that have had any impact on pig health and performance, notes Rowles. Benzoic acid has been the most promising of acidifiers to date, adds McKean.

Ileitis, caused by the Lawsonia intracellularis organism, is a big challenge for the Danes today, Rowles adds. Antibiotic use apparently suppressed the expression of ileitis.

“Without nursery antibiotics used as growth promotants, they're seeing severe clinical signs of ileitis three to four weeks into a nursery,” he says.

An ileitis vaccine has not been approved for use in Denmark. “So producers must use products such as Tylan Soluble (Elanco Animal Health) in the water systems at a therapeutic level to keep ileitis under control,” Rowles continues. “They must also work harder at sanitation issues.”

Scott Hurd drew three observations from the AGP ban in Denmark:

  • Antibiotic treatment levels increased after the ban on growth promoters;

  • Antibiotic use labeled growth promotion is doing more than promoting growth because when Danish producers removed the product, pigs became diseased; and

  • The Danish policy on antibiotics has not improved public health, based on the number of Danes diagnosed with salmonella and campylobacter, and the increasing level of resistance levels in some of those organisms.

“If you look at locally acquired salmonellosis cases, the resistance levels are actually increasing. They are also having problems with more cases of resistant Staphylococcus aureus, which may or may not be related to penicillin usage in animals,” says Hurd. He noted that penicillin use has increased 100% in animal therapy since the growth promotant ban.

Rowles says the most notable comment was made by a large Danish producer who hopes the U.S. will also ban antibiotic use for growth promotion because it would level the playing field.

Antibiotics Attacks Are Off Base

by Joe Vansickle, Senior Editor

A University of Minnesota veterinary researcher says critics of animal antibiotics ignore the value of improved performance at the expense of misguided concerns over animal welfare.

Their allegations couldn't be further from the truth, charges John Deen, DVM, associate professor of Swine Production Systems and director of the university's Swine Center.

“The decisions involved in antibiotic use in animal agriculture have been portrayed as being simplistic and biased.

“Worst of all, antibiotic use has been portrayed as being malicious toward the well-being of pigs. Such charges should be seen as an affront to the integrity of veterinarians and swine producers, and thus demand our attention,” states Deen.

In a White Paper on Antibiotics and Welfare, underwritten by Alpharma Animal Health, Deen proposes a three-step action plan:

  1. Describe in more detail the harmful effects of disease on the welfare of pigs. Pigs are susceptible to a variety of diseases producing a lot of pain and suffering. Producers need a broad range of tools to treat infectious pathogens, not limited by the constraints of therapeutic treatment in containing epidemics.

    “Arguing that antibiotics should be limited to treatment really ignores the main way we use antibiotics for controlling disease (prevention),” he adds. “We have to understand that we are working on a population basis. If you wait until the majority of pigs are sick, you are too late.”

  2. Investigate and describe the positive impact of antibiotics in animal populations. The proper use of antibiotics combined with improved housing and management has led to the virtual eradication of diseases like swine dysentery and greatly reduced problems with pleuritis and Actinobacillus pleuropneumonia.

  3. Identify responses to restrictions on use of subtherapeutic antibiotics. When the routine use of antibiotics is withdrawn, the results include increased levels of disease and compromised pigs, which hampers rather than improves animal welfare, says Deen.

“The focus of animal welfare has been based mostly on whether animals have the ability to turn around,” he says. Simply relying on the therapeutic use of antibiotics can produce more animal welfare problems related to mortality and morbidity.

However, the use of antibiotics can be employed effectively in a variety of animal health strategies. “They are used to treat clinical disease, prevent clinical disease in infected animals, and prevent the transfer of pathogens from infected to non-infected animals,” explains Deen.

NPPC Refutes Livestock Antibiotic Report

The National Pork Producers Council (NPPC) is denying claims of overuse of livestock antibiotics in a new report issued by the New York-based Environmental Defense.

The report, “Resistant Bugs and Antibiotic Drugs: State and County Estimates of Antibiotics in Agricultural Feed and Animal Waste,” claims to be the first study to estimate local use of livestock feed additives.

However, the estimates are based on a flawed 1999 report issued by the Union of Concerned Scientists entitled “Hogging It,” according to NPPC.

The report falsely accuses livestock producers of overusing antibiotics causing drug resistance in humans.

Estimates of antibiotic use reported by Environmental Defense have no scientific impact on human health, counters Harry Snelson, DVM, NPPC's director of Science and Technology.

“This report is not based on sound science and is essentially just an estimate of estimates,” he comments. “Real data — not estimates — from a legitimate source, the National Antimicrobial Resistance Monitoring Systems, continues to show that antibiotics produced for use in livestock have declined for the past four years.

“In addition, there is no scientific or medical proof that resistant bacterial infections that cause the greatest threat to human health have a connection with animals or antimicrobial use in animals,” says Snelson.

“Pork producers remain committed to the production of safe and wholesome products through sound, responsible and accepted practices,” he concludes.