Important health information about the potential role of probiotics and prebiotics in your horse’s digestive system.

Your horse’s digestive process—like yours—depends on a healthy population of beneficial microorganisms, or so-called gut bugs. Here’s how probiotics, prebiotics, and the products designed to contain them fit into the picture.

[READ MORE: Digestive Support]

What Are They?

Probiotics are live bacteria, yeasts, and other microorganisms that support digestive function by outcompeting bad gut bugs and improving or restoring good bugs. Prebiotics are fibrous foodstuffs that nourish the good gut bugs and help them thrive.

Already a multi-billion-dollar industry for human use, probiotic and prebiotic supplements are now marketed for horses and other animals, too.

Why the intense focus on gut bugs these days? Because we now know they’re extremely important. Your horse’s intestinal microbiome performs many critical functions, including aiding digestion, supporting his immune system, helping ward off disease, and more.

Factors that can negatively impact the equine gut microbiome include the administration of antibiotics (which can kill good bugs in addition to the bad ones they’re meant to destroy); stress from high performance or transport; sudden changes of diet; and certain infections, including those caused by clostridium or salmonella.

Can Supplements Help?

The effectiveness of probiotic supplements is still being researched. In vitro results have been promising, but studies involving live horses have been less conclusive, and more research is needed.

Still, such supplements are generally regarded as safe, and many experts do promote their use, especially for horses that’ve been on strong doses of antibiotics or are experiencing digestive disturbances like bloating and loose manure.

Be aware, though, that probiotic organisms must be alive to do their job, and many factors can affect their viability. Heat or oxygen can degrade them, so inadequate packaging and non-temperature-controlled storage are factors to watch for and avoid.

Prebiotics, by contrast, are more stable—they’re simply the plant fiber that feeds microorganisms, so they aren’t subject to the same viability concerns. Prebiotics are thought to help provide extra support to the immune system, especially in aging horses.

[READ MORE: Do’s & Don’ts for Horse Nutrition]

Bottom Line

As in all matters of your horse’s nutrition, ask your veterinarian for advice on whether a probiotic/prebiotic supplement might be beneficial for your horse. If you do choose to use such products, check the quality-control measures of the company you purchase them from. In particular, ask about testing that measures the amount of live bacteria in the product. 

Fiber & Prebiotics

Prebiotics are inert fiber compounds that pass undigested through the upper part of a horse’s gastrointestinal tract. They move into the hindgut—the fermentation chamber of the equine GI tract—where they feed the growth of the microorganisms colonizing there. Fiber sources that can serve as prebiotics include beet pulp, oat and soy hulls, and rice bran, among others.

[READ MORE: Understanding Feed Tags]