Prebiotics & Probiotics – Are these just fancy additives in horse feed?

There are many digestive supplements for horses on the market that include pre- and probiotics in their formula. Pre- and probiotics are scientifically proven additives that support your horse’s hindgut (more on the importance of the hindgut next!) and it’s important to understand how they function. Read along as we dive into an overview of how your horse’s digestive system works, and how you’re able to support healthy digestion.

The horse’s digestive system, feed, and the importance of the hindgut:

Your horse’s hindgut is an integral part of their digestive system. It hosts a whole ecosystem of microbes whose main job is to ferment roughage (hay, chaff, and other fibre sources). Microbial fermentation is your horse’s main way of sourcing energy and nutrients—simply put, microbes are the often overlooked heroes of the digestive system and the majority of what we are feeding is not actually feeding your horse, it is nourishing the microbial population.

Fibre supports the microbiome in the hindgut. However, if sugars and starches spill into the hindgut without being digested properly first, then it can be hugely problematic and can trigger digestive disorders. Most horses are capable of handling some amount of starch/sugar in their diet, but we must take care to not overfeed them—too much starch/sugar can leak into the hindgut where they rapidly ferment. This fermentation process produces lactic acid, heat, and gas, all of which can upset the balance of the microbiome. When the microbiome is upset it can kill off the beneficial microbes, decreasing the ability to breakdown feed and create nutrients, which is detrimental to your horse’s overall health and wellbeing.

Microbial death can also release a toxin. In an upset hindgut, this toxin may enter the bloodstream and lead to a condition known as endotoxemia, which can lead to laminitis, shock and even death if not treated promptly.

Keeping the horse’s hindgut happy and healthy is key to your horse’s overall health and wellbeing.


What is a PREBIOTIC and how do they benefit the horse?

A prebiotic is a non-living feed additive that supports beneficial gut microbes. Some prebiotics have a protective effect in preventing pathogenic organisms from inhabiting the hindgut. When the microbial population of the hindgut is healthy it prevents these non-favourable organisms from growing and causing disease. Research has also shown that horses receiving a prebiotic (Mannan-oligosaccharides MOS) demonstrated improved performance, which highlights the importance of supporting a healthy digestive system in sporthorses.

Probiotic powder for horse digestion

What is a PROBIOTIC and how do they benefit the horse?

A probiotic is a living microbe that is able to live in the digestive tract where it will boost digestive health. Probiotics are often used in human nutrition (yogurt and kombucha are great examples) to support our gut health. Research has shown that probiotics are also beneficial in equine nutrition.

The most commonly used, and most highly researched, probiotic given to horses is the live yeast Saccharomyces cerevisiae (SC). Studies have shown that SC is able to survive the journey through the digestive tract and populate your horse’s hindgut—this is a critically important point to note when you’re looking for a probiotic to feed, because there is no point adding a live organism to their diet if it’s unable survive and reach its destination.

It’s not just the internal journey that SC needs to withstand. This high-performing probiotic also needs to endure the manufacturing process, packaging, storage, being in the feed bin, and being eaten! SC has demonstrated its endurance in this respect.

In the hindgut, SC gets to work by:

  • Improving fibre digestion;
  • Stabilising the microbial population;
  • Improving energy production.

These are all very beneficial actions and are particularly helpful for horses that are in work, consuming high amounts of grain, or under stress. There are other probiotics that exist in equine nutrition, some of which show promise in terms of their viability and beneficial effect. However, they require more research to better understand their potential and their impacts.

Which horses may benefit from prebiotics and probiotics?

Supplementing your horse’s diet with pre- and probiotics is a good idea regardless of their relative health status because many horses are at risk of suffering from the negative impact stress and other dietary factors can have on their digestive function. Look at your horse and ask:

  • Is their manure normal?
  • Are they underweight or needing improved condition?
  • How is their coat quality?
  • Are they gassy?
  • Do they consume grain?
  • Are they under stress?
  • Are they a performance horse?

These are potential reasons why you may consider adding a pre- or probiotic into your horse’s diet. You can also support your seemingly healthy horse with pre- and probiotics as well—they’ll only increase the overall health, efficiency, and wellbeing of their digestive tract!

digestive support for competition horse

Pre- and probiotic supplements for the horse’s digestive health

Pre- and probiotics are included in our holistic digestive supplement, DIGEST & PROTECT®. Coupled with digestive enzymes and the amino acids, glutamine and threonine, which support digestive health, the ingredients in DIGEST & PROTECT® target and support gastric function from start to finish. This supplement is highly palatable and can be added directly into your horse’s current diet.

 Digestive support for horses

HYGAIN® DIGEST & PROTECT® provides complete digestive support in a palatable blend, formulated to stimulate digestion and promote the health of the digestive tract.

The formulation of DIGEST & PROTECT contains:

RED SEAWEED EXTRACT (Lithothamnion calcareum), is rich in a specific, highly effective source of calcium, known for its superior acid buffering properties.

DIGESTIVE ENZYMES support the breakdown of feed which improves digestion and the absorption of nutrients.

GLUTAMINE & THREONINE, amino acids assist with digestive health. Included to ensure adequate supply to support mucin synthesis and cell regeneration.

CONCENTRATED SLIPPERY ELM traditionally used for gastric challenges. Slippery Elm contains mucilage factors which act as a coating agent.

CURCUMIN, is the active compound in Turmeric known for its powerful antioxidant action.

PREBIOTICS have a defined mode of action, promoting a healthy gut and supporting natural defences essential for optimum health and performance.

PROBIOTICS enhance fibre fermentation and stablilise the microbiome, stimulating activity of beneficial bacteria in the digestive tract.

MYCOTOXIN BINDER traps and expels mycotoxins to protect and support healthy gut function.

ANISEED flavour is highly palatable for horses.

Equine digestive supplement

We also include pre- and probiotics in many of our feeds, like HYGAIN BALANCED®, SHOWTORQUE®, EQUINE SENIOR®, RELEASE®, and GROTORQUE®.


Understanding the way your horse’s hindgut functions and impacts their overall health is the first step in learning how to care for and support it. Although we may not be able to allow horses free rein to graze naturally in most domestic environments, we are still able to provide them with what they need to maintain healthy GI function. High-quality pre- and probiotics like the ones found in DIGEST & PROTECT® are an excellent addition to any horse’s diet and they can be fed without negative impacts to their digestive health. They’re a great way to ensure that your horse is happy, healthy, and comfortable year-round.

If you still have questions about the importance of digestive health, or you’re unsure if your horse could benefit from adding a pre- and probiotic to their diet, our team can help. Our expert nutrition advisors at Nutrikey offer a free diet analysis that is simple, fast, and accessible to all levels and disciplines of horse owners. The team will review your horse's current diet, considering all of their lifestyle factors to provide a diet plan that will help them look and feel their best. Visit or reach out to


Jouany, J , Medina, B, Bertin, G, & Jullian, V, 2009, ‘Effect of live yeast culture supplementation on hindgut microbial communities and their polysaccharidase and glycoside hydrolase activities in horses fed a high-fibre or high starch diet’, American society of animal science. 2844-2852.

Kauter, A, Epping, L, Semmler, T, Antao, E, Kannapin, D, Stoeckle, S, Gehlen, H, Lubke-Becker, A, Sebastian,G, Wieler,L & Walther,B, 2019, ‘The gut microbiome of horses: current research on equine enteral microbiota and future perspectives’, Animal Microbiome, vol.14, no.1, pp.1-15.

Khoder, G, Menhali, A, Al-Yassir, & Karam, S, 2016, ‘Potential role of the probiotics in the management of gastric ulcers (Review)’, Experimental and therapeutic medicine, pp. 3-17.

Pandey,K, Naik,S,& Vakil, B, 2015, ‘Probiotics, prebiotics and synbiotics- a review’, J Food Sci Technol, vol. 52, no. 12, pp7577-7587.

Van Saun, R, 2008, ‘Equine Microbial Supplements: Yeast, Prebiotics and Probiotics’, ACVIM, pp.1-6.

Venable,E, Bland, S, McPherson, & Francis, J, 2016, ‘Role of the gut microbiota in equine health and disease’, Animal Frontiers, vol.6, no. 3, pp 43 – 49.

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