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Research r...WeanersTrial report 778

Trial report 778: Effect of zinc and organic acids on diarrhoea in the weaner period

Diarrhoea treatments dropped significantly when organic acids were added to weaner feed. Mortality also dropped significantly when acid and zinc were added to the feed.


This trial investigated the effect of adding organic acids and zinc to weaner diets on treatments for diarrhoea, mortality and productivity in weaners. The trial was conducted in one herd with established diarrhoea problems caused by E. coli O149 and Lawsonia towards the end of the weaner period. The trial comprised three groups, 40 replicates and a total of approx. 3,200 pigs.

Group 1 (control):  Control diet. 
Group 2 (acid): As 1 with the addition of 1% lactic acid, 1% formic acid and 0.5% benzoic acid. 
Group 3 (acid + zinc): As 2. In addition, the pigs were given 2,500 ppm zinc the first 14 days post-weaning. 

There were significantly fewer treatments for diarrhoea when organic acids were added (group 2) and when acid was added for the entire period in combination with additional zinc the first 14 days post-weaning (group 3). Mortality was furthermore significantly reduced in the entire weaner period when acid and zinc were added to the feed (group 3). 

Based on daily gain and feed conversion, the production value was calculated using the same feed price in all groups. There was no significant difference in production value between the three groups, which means that the pigs did not grow faster or utilized the feed better even though 2.5% organic acids were added.

If health and productivity are calculated in the same index, it is revealed that the pigs in group 3 obtained the highest index and thereby the greatest economic value per pig. There is a difference of approx. DKK 8 per pig compared with group 1. This is the actual difference one must pay for the increased costs of adding acid and zinc.

Overall, the trial showed that feed to which 2.5% organic acids were added had a slightly less reducing effect on the prevalence of diarrhoea in the weaner period. Feed to which 2.5% organic acids were added in combination with 2,500 ppm zinc the first 14 days post-weaning significantly reduced the prevalence of diarrhoea and mortality. Daily gain and feed conversion were unaffected by whether acids and zinc were added to the feed. 


Updated: 22.01.2007


Lisbeth Jørgensen

Programme manager

Tel.: +45 3339 4301



Markku Johansen

Senior project manager, veterinarian

Tel.: +45 3339 4941