It is still permissible to give sick animals antibiotics. But in the 1970s many countries began mixing low doses of antibiotics into fodder as a matter of course, witrh the aim to enhance production. Sweden was the first country that prohibited this in 1986. In the second half of 1986 and in 1987 the effects were evident. Piglets contracted more diseases, and twice as many litters had weaning diarrhoea, with serious consequences. Mortality increased by 1.2% at national level, and one week's additional feeding was needed before the piglets could be sent to the slaughter pig cages since their weight had to be 25 kg. Swine dysentery that had been almost unknown increased dramatically and also affected slaughter pigs.
When the antibiotic shield was removed, diseases had to be prevented in some other way. The prohibition therefore helped in the long term in improving the health of Swedish pigs. Up till then it had not been particularly common to feed up one age category per cage, since the herds were relatively small. Now – also for the sake of profitability – larger herds began to be used. Farrowing pens could be built which, after emptying and cleaning, could be filled with sows that farrowed at the same time, which effectively prevented older animals infecting the younger ones. Many small herds joined cooperative sow pools and could have the whole herd farrow simultaneously at intervals of 16 weeks. There was then time for hygienic measures between farrowing and to feed up the animals to the required weight of 25 kg.
Feeding in stages
As early as 1986 there was feeding in stages, from 25 to 100 kg, but small pigs were sometimes kept back until the next input in order to reach the correct slaughter weight and thus provide a higher income. This can be expensive in the long run since it may spread infection to the next stage, and the pigs that grow most slowly are probably not the ones that are healthiest. This practice, in principle, stopped after the prohibition, not least because of the risk of dysentery. But the method is still tempting at times of downturn in the economy. Entry protection has increased thanks to lobbies where staff and visitors must change into approved clothing. Foreign and sometimes also Swedish visitors must have been "pig free" for some time before they can be admitted. Because of infection prevention rules, production will increasingly be shown through web cameras in future.
Improved housing and long term production planning form the basis of a high disease prevention standard and good entry protection.
Strategic veterinary work and the fact that we avoid a lot of microbes which cause problems on the continent further contribute to production today being in fact higher than if we employed general antibiotic addition to the fodder.
Sweden has encountered great international respect, and Europe is now following suit and prohibiting general addition of antibiotics to fodder. Our experience demonstrates that the use of antibiotics can be reduced with productivity maintained or increased, which also decreases the risk of antibiotic resistance being developed.
Specifically targeted measures have also contributed to enhancing and retaining the health status of Swedish pigs. Aujeszky's disease, pseudorabies, could be eradicated in 1997. Porcine Reproductive and Respiratory Syndrome – PRRS - was diagnosed in seven herds in 2007 and immediately eradicated.
is professor at the unit for animal health and antibacterial strategies, National Veterinary Institute SVA
The use of veterinary medicine antibiotics has decreased by 60% compared with the time prior to the prohibition. It is certain that this low usage contributes to the very favourable position that Sweden has regarding resistance to antibiotics. This is described annually in a report published by SVA and Strama VL (SVARM report). Sweden was the first. In 1986 we stopped general addition of low doses of antibiotics to the fodder of animals that were not sick. In the same year, diseases among piglets increased. Later experience has however shown that is it possible to reduce the use of antibiotics while maintaining or increasing productivity. In addition, resistance to antibiotics may decrease.