Environmental Benefits of Growth-Promoting Antibiotics

Introduction

Growth-promoting antibiotics (or, more correctly, antimicrobials) are products which are incorporated into animal feed to create favourable conditions in the animal's intestine for the digestion of food. They are mainly used to improve feed conversion capability (which means less food is required per unit liveweight gain) and hence growth rates of the animal without laying down excessive amounts of fat.

Growth-promoting antibiotics are authorised under stringent European legislation requiring independent expert scrutiny. Antibiotics licensed as growth promoting antibiotics have been specially selected to remain in the gut, not to pass into the animal’s body, and especially chosen as compounds not used as human or veterinary therapy. Nevertheless, this class of products is being withdrawn in Europe, so the use of growth promoting antibiotics is being phased out by the start of 2006. (For more information on antibiotic growth promoters, see NOAH briefing document 16 ‘Growth promoting antibiotics – your questions answered’)

So, how can these products help the environment ?

The action of growth-promoting antibiotics

The efficiency of an animal’s digestion is dependent on the micro-organisms which live naturally in its digestive tract – some improve digestion, others make it less effective. Added to the feed of pigs, poultry and cattle, growth-promoting antibiotics neutralise adverse micro-organisms which live in the animal’s gut. They help the intestine absorb more nutrients and water, and so the animal grows well, making the best use of its food. The animal benefits by being less likely to suffer intestinal upset and can cope with changes to its diet without problem. Consumers benefit from the availability of good, wholesome food, tailored to their demands, at an affordable price.

The practical benefits to the environment and the world we live in

It is important to remember that very small changes in individual animals can add up to huge changes when taken globally. Growth-promoting antibiotics benefit the world we live in and the environment in several ways:-

1. The use of growth-promoting antibiotics means that less food is needed by animals, requiring less farmland.

For example, 8 million pigs fed with a growth-promoting antibiotics would require 70,000 tonnes less feed during fattening. (There are approximately 122 million pigs in Europe1).

2. The healthier intestine of animals fed with growth-promoting antibiotics absorbs more nutrients. Therefore, fewer unused nutrients are lost into the environment, resulting in a cleaner world.

Nitrogen and phosphorus in particular can be a problem, especially when they enter waterways where they can cause eutrophication (the uncontrolled growth of algae, which depletes oxygen supplies harming fish and micro flora).

It has been estimated that in France, Germany and the UK, the removal of growth-promoting antibiotics from the diets of pigs, beef cattle and poultry, would result in an increase of 78,000 tonnes of nitrogen and over 15,000 tonnes of phosphorus being released into the environment each year.

3. The animal's healthier intestine produces less waste gases into the air.

Animals given growth-promoting antibiotics excrete up to 15% less of the potent ‘greenhouse gas’ methane and up to 33% less ammonia. As an example, in the same three countries as mentioned above, cattle given dietary enhancers are thought to excrete 1,246 million cubic metres less methane per day into the air.

4. Animals given growth-promoting antibiotics consume less water and excrete less manure with a lower water content. Getting rid of manure can be a major problem and there are strict rules where it may be spread in relation to water courses, human population, etc.

As an example it has been estimated that the use of growth-promoting antibiotics in the EU pig herd means a reduction of 7 million cubic metres of waste manure per year (the equivalent of 3,500 Olympic size swimming pools)

Conclusion

The use of growth-promoting antibiotics has more benefits than just the production of quality meat and milk. It also has positive benefits to the world we live in. Their use leads to:-

1. Less feed required for animal production.
2. Reduced levels of nitrogen and phosphorus, methane and ammonia entering the environment.
3. Less water consumption.
4. Dramatic reductions in manure production.
5. Reduced requirement for fossil fuels for the transportation of feed and manure.
6. Less land needed.

There is concern that the phase-out and the trend to replace these products by substances and systems which have not been subjected to the same independent scrutiny could cause problems in years to come.

1 Eurostat 2003

Updated April 2004