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Producing pigs without zinc oxide

August 12, 2020

In less than two years the use of zinc oxide (ZnO) for the control of post-weaning diarrhoea will be banned, writes Liz Donnelly, Pig Adviser CAFRE. In June 2017 a decision was made to ban the medicinal use of ZnO, with a five year phase out period. This means ZnO cannot be included at current levels to control post-weaning diarrhoea after June 2022.

Zinc oxide is still widely used in the Northern Ireland (NI) pig industry for the control of diarrhoea in weaned pigs. I recently asked 25 farmers about the use of ZnO and 21 replied they were still using it. Of the 21 using it some were only including it in the creep, having recently removed it from the link.

Weaning is a very stressful time for pigs. They are abruptly removed from their mother, handled or even transported, moved to a new house with a completely different environment, mixed with other pigs and put onto an ad-lib dry diet. All these changes put the pigs under enormous stress leaving them more prone to diarrhoea.


Over the past ten years there has been an increase of almost 25% in the number of pigs weaned per litter. The average weaned is now 13.2, with the top 25% of units averaging 14.5 weaned. This increase has resulted, not only in lighter pigs at weaning, but also more variable weaning weights. This, combined with the increasing pressure to reduce antibiotic use, will make rearing pigs without the use of ZnO even more of a challenge.

Is there a ‘silver bullet’ alternative to ZnO? I asked Dr Ramon Muns, Head of Pig Research at AFBI, this question and he simply replied, “No.” “As we don’t know how ZnO works it makes it very difficult to find an alternative.”

As Ramon says “to prepare for life after zinc farmers will have to work towards making the weaning process as smooth as possible. This means putting extra effort into weaning heavier pigs, reducing weaning stress by not mixing litters, improving hygiene and having a strict all in/all out system. Feeding and nutritional management will also play an important role. You want your pigs to start eating as soon as possible and this begins with good creep feed management during lactation. Diets will also change. Crude protein levels will be reduced and non-fermentable fibre will be included in rations.”

To help farmers produce pigs without zinc oxide AFBI is currently carrying out DAERA funded research on alternatives. The research includes investigating the effect of extended lactation length and therefore heavier weaning weights and feeding lower crude protein diets. The research will look at not only the effect of feeding lower protein diets but also how low diets can go in terms of crude protein. Ramon is also planning to start a project next year looking at strategies that influence gut microbiota, with the aim of improving post-weaning health.

With over 80% of pig farmers in NI still including ZnO in diets for weaned pigs a combined effort by farmers, vets, nutritionists, researchers and advisers is required to prepare pigs and farms for life after zinc. As there is no common solution the challenge is for each of you to find out what works on your farm. Focus on this is required sooner rather than later as the ban is getting ever closer. For many farms a combination of changes will be required and it will take time to determine these changes.