Ulcers? The science behind Prebiotics & Probiotics

Ulcers in horses Gastrosafe

What really works best for horses with EGUS.

Prebiotics or Probiotics?

This is a popular topic for the equestrian world as horses suffering with ulcers and gut imbalances is becoming more apparent to owners and riders. So, Synovium look at what is really best to support them, prebiotics or probiotics? Our leading vets often get asked this question, so we decided to carry out extensive trials and look at the scientific evidence to conclude their professional verdict on this ulcer topic.

Whilst some research has been done for using probiotics on horses (mainly in foals) it is neither extensive nor conclusive. Research of supplementing probiotics is largly based on human research and not horses. Horses are mostly grass eaters and do not eat meat like humans, so we cannot compare the two!

Probiotics, what are they?

Probiotics are live microorganisms added to feed or supplements. It is believed that when fed to horses, it increases the good bacteria needed for digestion to counteract digestive upset caused by an imbalance in bad bacteria over the good bacteria within the hindgut. Unfortunatly, there is no conclusive research in horses that Probiotics works, and some studies have concluded that some types of probiotic causes further upset, as each individual horse’s microbiotics are unique, determined at just a few days old. There are too many factors which can affect the quanity and types of good bacteria in any individual horse, from what they are fed to biological chemistry, to fully understand if probiotics make any difference.

Lets understand how the horse’s gut works..

Horses are hindgut fermenters, therefore meaning that the large intestine is where breakdown of fibre takes place. Fibre is the main component of the horse’s forage which is broken down by microorganisms to produce essential nutrients that the horse absorbes.

Because the hindgut is geared for fibre fermentation, it is susceptible to upset due to receiving large amounts of undigested sugars.

The ideal balance between these good microbes and harmful bacteria can be easily upset when:

  • undigested starch from concentrated feeds ends up in the hindgut
  • horses have restricted grazing
  • there is a sudden change in forage/ feed (7-10 days at least is recommended)
  • stress and anxiety 

It is important to keep the balance of good and bad bacteria exactly right for each individual horse.


The science behind Prebiotics

Prebiotics are a non-digestible food source to support your horse’s existing good gut microbes. Unlike probiotics they do not contain live bacteria. Prebiotics support the horses good bacteria, for optimum health, by stimulating the growth and activity of the existing microorganisms. So the helpful bacteria remain healthy to prevent the bad bacteria thriving. Studies prove the benefits of supplementing horses with Prebiotics for gut health.

Ulcers in horses Gastrosafe

Synovium® Gastrosafe

Our leading vets have studied the scientific evidence on horse’s gut support and undertaken extensive trials to provide a supplement that effectively supports the horse’s front and hind gut. Synovium Gastrosafe contains a unique veterinary formula which supports a healthy stomach environment and aids digestive function. It helps to control gastric acidity in horses, providing essential prebiotics, whilst supporting the natural anti-inflammatory processes within the gut. It is award winning and has been scientifically proven to support horses during or after veterinary treatment for ulcers when fed for at least 6 weeks. Always ask advice of your vet if you suspect your horse has ulcers.

Gastrosafe contains

(daily dose is for the maintenance of an average 500kg horse)

  • Calcium Carbonate 10,000 mg per daily dose – A natural buffer against stomach acid
  • Laminaria hyperborean 5, 000 mg per daily dose – Seaweed, very palatable vitamins, minerals and trace elements to help protect the stomach wall
  • Magnesium Hydroxide 5,000 mg per daily dose – helps to neutralise stomach acid and is often used to calm horses who easily get stressed or anxious.
  • Fructooligosaccharides 5, 000 mg per daily dose – Prebiotics, a natural feed source for good gut microbes
  • Glutamine Peptides 1,900 mg per daily dose – an essential amino acid to help maintain a healthy stomach lining and replenishes the natural L-glutamine which is often lost through stress
  • Threonine 2,360 mg per daily dose – an important amino acid for optimal GI tract health by assisting mucin production to support a smooth gut function and nutrient absorption. Also guarding the gut from bad bacteria and toxins.

Full details can be view on our website www.synovium.co.uk


It is still an ongoing study to understand what is best to feed your horse for gut support and therefore it is always recommended to speak to your vet for advice. There are many theories on Probiotics but nothing concrete, unlike with Prebiotics. Synovium Horse Health bases its supplements on only proven science and trials.


Synvoium Horse Health founder & FEI Dutch Veterinarian, Drs SHL Donker DVM. Manging Director Synovium UK, Miss VA Hipkins.


Gastrosafe ulcer supplement for horses