The threat of antibiotic resistance to human and veterinary medicine from the excessive use of antibiotics in livestock is moving up the agenda.
In March McDonald’s unveiled their Global Vision for Antimicrobial Stewardship in Food Animals. Key goals for this vision include aiming to eliminate the use of medically important antimicrobial (defined by the WHO) for growth promotion, and encouraging animal production practices which eliminate of reduce the need for antimicrobial therapies. In the same month the restaurant chain announced that chicken served in it’s 14,000 outlets in the US would come only from birds not treated with medically important antimicrobial.
New Zealand vets have recently announced that they will aim to eliminate the countries use of antibiotics in animal agriculture by 2030. According to Dr Steve Merchant of the New Zealand Veterinary Association (NZVA)
“By 2030 New Zealand Inc will not need antibiotics for the maintenance of animal health and wellness”
It is questionable whether this is a realistic goal. New Zealand is already the third lowest user of antibiotics in animals in the world, due to the dominance of grassland based sheep and dairy farming. New Zealand dairy cows receive only a third of the antibiotics of dairy cows in the US. According to the New Zealand Poultry Association the most commonly used antibiotic for poultry is zinc bacitracin, a type rarely used in human medicine, and that annually only 0.003% of the New Zealand poultry flock receive any antibiotic which can also be used in as a therapeutic treatment in humans. The latest data available (2009-2011) shows that antibiotic use in New Zealand is falling. Sales of zinc bacitracin in 2010/11 were 20,476 kg by active ingredient compared with 18,057 in 2004/5. This trend is being driven by changes in practices in the poultry sector, with a significant growth free range production.
However, experience from elsewhere shows that use of antibiotics can never be completely eliminated. Denmark was the first country in the EU to introduce a voluntary ban on the use of non-therapeutic use antibiotics in food animals in 1998, and a compulsory ban in 2000. It is claimed that total use of antibiotics fell by 26% from 1998 to 2000, however therapeutic use increased by 263%! The gradual introduction of better husbandry practices, and alternative control measures such as vaccinations can in time bring down therapeutic use. The latest data from Germany indicates a fall in antibiotic use by 15% during 2014, however German vets reject the idea of a blanket ban on certain substances for animal welfare reasons. Sick animals will always need treatment on welfare grounds, and whilst good husbandry can minimize the risk of disease, it cannot eliminate it. AgCarm the body that represents the manufacturers of agro-chemicals and animal health products in New Zealand has stated that the goal is unrealistic, however they did share the vets concern over the development of resistance.
If complete elimination is not possible what can be done? Judicious use of antibiotics is about maintaining the effectiveness the drugs rather than replacing them entirely. NZVA policy states that before treatment there must be evidence of bacterial infection, and that the appropriate selection of an antibiotic is critical. antibiotics should be a part of and not a replacement for an integrated disease control programme.