Digestive-Shield™ - Only from Nutrena® | Nutrena

In 2003, the Nutrena® brand revolutionized the feed industry with the debut of the original SafeChoice® Horse Feed, the first controlled starch horse feed to hit the market. In 2023, Nutrena® is revolutionizing equine nutrition again by introducing an exclusive Digestive Shield technology for complete gut health and immune support. Digestive Shield™ with controlled starch, pre + pro + postbiotics and calcite helps support the entire digestive tract.

Keep reading to learn WHY gut health is important, WHAT Digestive Shield™ is, and HOW Digestive Shield™ supports overall gut health.

Understanding a Horse’s Gut Health

Why Is Your Horse’s Gut Important?

Maintaining a balanced digestive system helps support overall horse health. The digestive tract, or “gut,” of the horse is responsible for breaking down (digesting) feed ingredients and absorbing nutrients present in them.  The microbial population within the gut also plays a role in producing key vitamins, in addition to maintaining gut health. By some estimates, the gut is responsible for 70% of the horse’s immune system. Gut health refers to both the integrity of the gastrointestinal tract and the balance of microorganisms that live there.

How Are Microorganisms and Gut Health Related?

Microorganisms live symbiotically in the horse’s digestive system. Mostly concentrated in the hindgut (cecum and large intestine), these microorganisms break down the fiber in feed and hay. This is done by deconstructing complex molecules to release the nutrients and allow the synthesis of energy substrates and important vitamins. Those nutrients are then absorbed through the intestines into the bloodstream, where they become available to cells in the body to support maintenance, growth, and activity. 

Gut microorganisms include bacteria, protozoa, fungi, and even viruses. The specific combination of organisms acts as a unique ecosystem within the horse.  You may also hear this balance of microorganisms referred to as a “healthy microbiome,” or “healthy gut flora.”  When the populations of microorganisms in the gut are balanced, the horse can achieve maximum nutrient digestion from its forage and feed.

Why Digestive Shield™ Is the Answer

What is Digestive Shield™?

Digestive Shield is a new technology, exclusive to the Nutrena® brand, that supports gut health from end-to-end with a unique combination of controlled starch, calcite and pre + pro + postbiotics. Digestive Shield™ is one more way Nutrena® continues to work to promote the health and well-being of horses. To better understand how Digestive Shield™ works to protect horses from the inside out, let’s look at the components.

Calcite for Horses

As the horse eats, food passes first into the stomach.  The stomach is designed to serve as a mixing vat and begins the digestive process through the addition of strong acids to the food mixture.  Because horses were designed to eat continually, they continuously produce stomach acid, not just after meals.  When horses are instead meal fed or go for extended periods without food, this stomach acid on an empty stomach can be problematic.  Normally, when grazing, horses produce a great deal of saliva that tends to buffer stomach acid.  However, if grazing/chewing is reduced, saliva production is also reduced, and stomach acid can get out of hand. 

One approach to maintaining healthy stomach acid levels is the use of buffering agents to help maintain a healthy pH of the stomach between meals.  Calcium in the diet is a natural buffering agent, however, studies have shown that a marine-derived calcium, known as calcite, has up to 2x greater buffering capacity when compared to calcium carbonate normally used in horse feeds2.  Calcite’s greater buffering capacity can be attributed to its more porous surface area. 

In addition to helping serve as a buffer in the stomach, research has also shown a beneficial buffering effect of calcite in the horse’s hindgut (cecum and large intestine)3.  Helping to buffer or maintain hindgut pH can help keep the horse’s hindgut function normally. 

Prebiotics, Probiotics, Postbiotics for Horses

Much like humans, a horse’s digestive tract is home to billions of microorganisms that help break down and process the food it eats. Let’s take a closer look at these nutrient-munching microbes and how we can support them.

  • Prebiotics: These are the nutrients that beneficial bacteria eat – in other words, “the fuel” for the “good bugs.”  Prebiotics help maintain the healthy population of microorganisms when, for example, there are sudden changes in a horse’s diet, which helps to reduce digestive upset. They can support the growth and activity of beneficial microorganisms, which benefit the horse by enhancing the absorption and retention of certain nutrients. 

    The prebiotic used in Digestive Shield™ comes from chicory root. Chicory root is broken down into a prebiotic known as inulin. Inulin is particularly beneficial to the horse as it is not digested in the stomach or small intestine allowing it to make its way to the microbes of the hindgut.
  • Probiotics: These are living microorganisms — “the factories” — that can be added to a horse’s diet to help balance its gut flora population.  Providing more beneficial bacteria has been shown to increase nutrient digestibility and shift the balance of microbes in a positive way. Probiotics in Digestive Shield™ include beneficial strains of Lactobacillus, Enterococcus, Bifidobacterium, and Bacillus. 

    To be effective, cultures in a probiotic must be alive. In some cases, the processing of Probiotics destroys the cultures. Probiotics in Digestive Shield™ have been tested to ensure they remain viable after pelleting.5

Probiotics can be measured on a feed tag by the measure of Colony Forming Units (CFU) per pound of feed declared on the tag.  In general, the higher the CFU/lb. level, the better, as long as you are comparing similar strains and products of equal stability.  Understanding the value of specific strains, such as the specific functionalities of Bacillus subtilis can also be useful as not all probiotic strains play the same role.

  • Postbiotics: When yeast and/or bacteria are fermented outside the animal they create biproducts known as metabolites that can have beneficial health effects.  A postbiotic is the combination of inanimate microorganisms, both intact and cell wall fragments/structures, and their metabolites that when fed to an animal confer a health benefit.

Postbiotics are often considered “the goods” if the microorganisms themselves are the factories.  While microorganisms within the animal certainly produce “goods” in the form of volatile fatty acids (an energy source), vitamins, and more, fermentation of yeast and bacteria outside the animal creates a unique profile of metabolites in a consistent manner.  These metabolites when consumed in the feed as postbiotics then serve as bioactives and signaling molecules for a variety of physiologic functions including enhanced immune response.  The signaling molecules can also support other microbes to further stabilize the microbiome.

In summary, the combination of pre + pro + postbiotics in Digestive Shield™ provide many benefits to horses:

1. Horses were built to digest fiber, so forage (hay or pasture) should be the primary component of the horse’s diet. The right combination of pre + pro + postbiotics helps support digestion of nutrients from forage (increase fiber digestibility). This means that you can get more calories and nutrition from the same amount of feed and forage.

2. The gut is an integral part of the immune system.  Maintaining a healthy gut helps support a healthy immune system.

3. Supporting gut health also helps support haircoat, hoof quality, body condition, and muscling.

Key Takeaways: Digestive Shield™ for Gut Health and Immune Support

You now have an understanding of how a balanced gut can lead to better overall health for horses and the role that Digestive Shield™ plays in supporting that. Keep in mind:

  • Calcite can help maintain a healthy stomach pH after and between meals through its superior buffering capacity.  This may help the horse support a healthy stomach lining.
  • Pre + pro + postbiotics along with naturally occurring “good bugs” work in the horse’s hindgut to aid in the digestion process, promote beneficial microbes, and support optimal immune health .

The goal when it comes to gut health is to maintain normal homeostatic balance, even in situations that would typically cause a disruption, so the horse can carry on through it without negative side effects. That is why Nutrena® brand horse feeds with Digestive Shield are the partner in protection that can help keep your horse looking and feeling its best, from the inside out.


SafeChoice bags

SafeChoice® - Now With Digestive Shield



1 Sykes, B.W., et al. “European college of equine internal medicine consensus statement—equine gastric ulcer syndrome in adult horses.” Journal of Veterinary Internal Medicine 29.5 (2015):1288-1299.

2 Moore-Colyer, M., et al. “An in vitro investigation into the effects of a marine-derived, multimineral supplement in simulated equine stomach and hindgut environments.” Journal of Equine Veterinary Science 34.3 (2014):391-397

3 Liburt, N., et al. “Effect of a marine-sourced calcium on fecal pH in horses.” Journal of Equine Veterinary Science 100 (2021):103531.

4 Burke, M.L., et al. “Bacillus subtilis strain PB6 demonstrates growth inhibition toward equine-specific bacterial pathogens.” Journal of Equine Veterinary Science 58 (2017):84-88.

5 PrimaLac Study #SL-01-1.  April 2003. PrimaLac Pet DFMs Remain Stable Through the Heat and Pressure of Extrusion. Star-Labs/Forage Research Inc. P.O. Box 601, St. Joseph, MO 64506. USA.

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