BLOGS > COMPARATIVE TRIAL: THE IMPACT OF POST-WEANING DIARRHEA

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COMPARATIVE TRIAL: THE IMPACT OF POST-WEANING DIARRHEA

19/09/2025 Pigs

During the abrupt weaning process, which is based on age rather than body weight, piglets are exposed to multiple stressors. Separation from the sow, regrouping with unfamiliar pen mates, a new housing system, and most importantly: the dietary shift from highly digestible milk proteins to plant proteins, all add to the challenge.

The latter are generally lower in digestibility and may contain antinutritional factors. In combination with the immature digestive system, these factors increase susceptibility to intestinal pathogenic bacteria and the impact  on piglet growth becomes clear: post-weaning diarrhea (PWD). This condition not only threatens intestinal health but also undermines growth and overall piglet performance in the nursery phase.

To reduce these losses, different nutritional strategies are applied, such as lower crude protein levels in the starter diet, selecting highly digestible protein sources, and adding feed supplements that reduce intestinal pathogenic bacteria activity and/or improve intestinal resilience. Benzoic acid is one such additive, known to reduce PWD and support growth up to 25 kg live weight. However, esterified fatty acids often show stronger antibacterial effects than their free counterparts. This led to a comparative trial, evaluating whether α-monobenzoate glycerol could outperform a reference diet (benzoic acid, commonly used in the market) in post-weaning piglet diets.

MATERIALS AND METHODS
  • Animals: 300 weaned piglets with an average body weight of 6.5 kg were delivered at the farm. At arrival, piglets had health issues: 65% had acute diarrhea, related to an coli infection and 50% had snout inflammation, which was accompanied with sinusitis caused by Staphylococcus spp. Moreover, 35% of the piglets weighed less than 5 kg.
  • Allocation: At arrival, piglets were weighed and allocated to six pens based on body weight (50 piglets per pen), having two replicate pens per treatment.
  • Diets: The basal diet was a PreSafe piglet feed concept that was gradually replaced by a commercial piglet starter during the first 14 days post weaning. Subsequently only the piglet starter was fed. Diets were either supplemented with 5.5 kg/t of a benchmark (99.9% benzoic acid), 2.0 kg/t Olus®C7 (30% α-monobenzoate glycerol) or 2.75 kg/t Olus®C7. All diets were supplied as pellets.
  • Duration: No metaphylactic medication was administered during the 31-day experimental period.
  • Measurement: Piglet body weights at start and end, and feed supply were recorded per pen.

 

RESULTS

Production performance of piglets during the 31-day production period is given in the table:

Graph comparing reference diet (sodium benzoate) and Elan®C7 in weaned piglets, showing performance improvements related to post-weaning diarrhea.

All piglets started to eat rather quickly, and diarrhea stopped within 24 hours after starting with the PreSafe piglet feed concept. In the following days snout inflammations alleviated.

  • Body weight gain of piglets fed the Olus®C7 diet at the lower dose was 1.3 kg/piglet (7.5%) higher compared to those fed the reference benzoic acid diet, whereas the higher Olus®C7 dose showed a similar BWG.
  • Olus®C7 stimulated daily feed intake and showed an improved FCR by 3.3 points at the low and 4.2 points at the high dose level compared to the reference benzoic acid diet.
  • The number of medically treated piglets was comparable across treatments.
  • It was reported that piglets with the Olus®C7 diets had cleaner skin and eyes.

From this small-scale experiment it was concluded that α-monobenzoate glycerol (Olus®C7) at 2.0 kg/t was more efficacious than the reference benzoic acid diet at 5.5 kg/t.

 

CONCLUSIONS

This comparative trial showed that supplementing piglet diets with α-monobenzoate glycerol (Olus®C7) improved feed intake, body weight gain, and feed efficiency compared to a reference benzoic acid diet, commonly used in the market.

At 2.0 kg/t, Olus®C7 resulted in:

  • +4.6% higher daily feed intake
  • +7.5% higher body weight gain
  • 3 points better FCR

These findings suggest that α-monobenzoate glycerol is a more efficacious option than benzoic acid for supporting piglet performance during the post-weaning period.

Learn more about how Olus®C7 can support piglet performance — contact our team today.

 

Professor Jan Dirk van der Klis, a man wearing glasses and a black blouse of Olus, standing for a sustainable green wall.

ABOUT THE AUTHOR

Jan Dirk van der Klis – Consultant Animal Nutrition

Jan Dirk van der Klis is a renowned poultry consultant with a PhD in Animal Nutrition from Wageningen University. Throughout his career, Jan Dirk has made noteworthy contributions to the industry. With his extensive expertise, he is offering valuable nutritional guidance to enhance the health and productivity of poultry. Jan Dirk’s profound knowledge and experience are pivotal in meeting the specific nutritional requirements of poultry and devising effective feeding strategies to yield optimal results. Since 2019, Jan Dirk has been working with Olus.

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