Wetenschap - 13 april 2011

Antibiotics in livestock farming: turning the corner?

The number of kilos of antibiotics used in livestock farming has been falling since 2007, but LEI is still not seeing a significant reduction in its annual sample survey among individual farms. What is more, resistance to antibiotics is increasing. But there is still reason for optimism, thinks Dik Mevius.

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kippen.jpg

Foto: .

FIDIN, the association for the suppliers of animal drugs, recently announced that antibiotics use fell by 12 percent in 2010, following a fall of two percent in the previous year. That is good news. The government wants use of antibiotics this year to be 20 percent less than in 2009, and to have halved in 2013.
Not committing himself
'It seems to be going in the right direction', says Dik Mevius, coordinator of the MARAN report, an annual review of the use of antibiotics in livestock farming and resistance to antibiotics. He is not committing himself though, because LEI's annual sample survey among livestock farmers gives a less clear picture. While it is true that the use of antibiotics among dairy cows and pigs bred for meat fell by more than 10 percent in 2009 and among calves bred for meat by four percent, use among broiler chickens remained constant while use rose by more than 10 percent among sows.
FIDIN measures the total number of kilos sold by manufacturers, whereas LEI measures the number of dosage days: the number of days in a year that an animal receives antibiotics. The latter is a better measure of actual use.
Kilo effect
It is clear that the use of antibiotics among dairy cows, and calves and pigs bred for meat fell in 2009, says Mevius, who works for the Central Veterinary Institute (CVI). These are large animals, so that has a big effect on the kilograms used. That kilo effect is less for small animals such as chickens, and the poultry sector happens to be a sector where use has been rising substantially over a long period and has still not fallen. As a consequence, resistance to antibiotics has risen in this sector. Nearly all chickens in the Netherlands have ESBL-forming bacteria that are resistant to antibiotics, says Mevius.
It is difficult to get rid of resistance to antibiotics once it has arisen. For example, there is still an E. coli bacterium wandering around with resistance to an antibiotic that has not been on sale for 20 years. Making substantial reductions in the number of kilos of antibiotics helps, says Mevius, but additional measures may also be necessary.
Registration
Even so, the tone of LEI and CVI's MARAN report is optimistic. The general message is that things are going in the right direction. 'That is a conscious choice', says Mevius. 'People in the sector are making a lot of effort to reduce usage.' He is referring to the registration system created by KNMvD, the professional association of vets, which records how much antibiotics each vet prescribes. What is more, the calf, pig and poultry sectors are going to start recording usage by livestock farmers in the context of Integral Food Chain Management.
'The idea is that registration should lead to improvement projects', says Mevius. 'The farmers and vets who use a lot of antibiotics can then personally be held to account for their behaviour. You want to get them working with you and taking responsibility for their actions. You can't impose something from above - this is not the DDR. I should make it clear: you do need animal drugs, livestock farmers and vets are allowed to use them, they are not illegal. What we are talking about is responsible use.'
His colleague Nico Bondt at LEI also takes an optimistic view. 'We have been preaching gloom and doom to livestock farmers for years. They weren't grateful for that but the message has finally sunk in. Use is being recorded and farm health plans are being drawn up. The foundations for improvement are being laid.'
Today Parliament will be debating antibiotics use with the State Secretary Henk Bleker.

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