Prebiotics are types of fibre that are given to horses as a food source for the beneficial microbes in the hindgut. Prebiotics support fibre digestibility, gut health, and nutrient assimilation in the hindgut.

Horses with disrupted digestive function, observed as bloating, discomfort, diarrhea, constipation, free fecal water, or intolerance to grain might benefit from prebiotics in the diet.

For horses that struggle with undesirable weight loss or hard keepers that need to gain weight, consider prebiotics to support the gut microbiome and increase nutrient absorption.

Prebiotics are soluble plant fibres that can not be digested by enzymes in the stomach or small intestine. This differs from probiotics which are living microorganisms.

Prebiotics reach the hindgut where they are broken down by specific microbes and function as substrates to stimulate the growth of probiotics. This helps the beneficial microbes proliferate and synthesize volatile fatty acids and vitamins that support a healthy gut and are beneficial to the horse.

The most common prebiotics are oligosaccharides which are long chains of sugar molecules that serve as an energy source for beneficial microbes. Fructo-oligosaccharides (FOS) are derived from chicory root. FOS primarily supports microbes such as Bifidobacteria.

Mannan-oligosaccharides (MOS) derived from yeast are added to equine diets as toxin binders. They work by binding to pathogenic microbes and toxins to limit their harmful effects. This helps support a healthy gut microbial environment and minimize inflammation of the intestinal wall.

Mad Barn’s Optimum Digestive Health (ODH) is a complete gut health supplement that contains Bio-Mos, a propriety prebiotic derived from yeast that has been shown to improve gut function in horses. ODH also supplies probiotics, digestive enzymes, and yeast to support hindgut health and feed efficiency.

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  • Prebiotics, probiotics & enzymes
  • Support hindgut development
  • Combats harmful toxins in feed
  • Complete GI tract coverage

Benefits of Prebiotics for Horses

A healthy gut is critical for supporting overall health and well-being of horses. The hindgut is home to trillions of micro-organisms that are necessary for digesting dietary fibre to meet the energy needs of the horse.

The hindgut is also the main site of synthesis for the water-soluble B-vitamins which have diverse roles in equine physiology.

Prebiotics nourish the beneficial microbes or probiotics, to help maintain a healthy gut environment and support efficient digestion and nutrient absorption.

Below are the top 6 science-backed benefits of prebiotics for horses:

1) Improved Tolerance to High-Grain Diets

High-grain diets are typically fed to performance horses to maximize energy supplied by the diet. However, rapid changes in the diet from high-forage to high-grain can negatively impact the hindgut environment.

Starch overload in the hindgut increases lactate production which lowers the pH, making the environment less favourable for fermentation of fibre and other complex plant carbohydrates. This lowers the pH of the hindgut, and in extreme cases can contribute to hindgut acidosis, colic and laminitis in the horse.

Adding short-chain FOS to a high-barley diet in mature geldings minimized shifts in microbial populations in the hindgut, suggesting prebiotic supplementation can be beneficial in reducing hindgut disruptions related to starch overload. [1]

2) Improve Digestion in the Hindgut

Fibre fermentation in the hindgut creates volatile fatty acids (VFAs) that are absorbed by the horse and used as an energy source. Shifts in the microbial populations can change the production of these and potentially leave horses in an energy deficit.

Horses given the prebiotic FOS for 10 days had increased levels of VFAs (acetate, butyrate, propionate) and lactate measured in feces. [2]

By providing prebiotics to nourish the microbes, they were able to produce more VFAs as an energy source for the horse. Horses with high energy demands, including growing and heavily exercised horses would likely benefit from prebiotics to increase VFA production by the hindgut.

3) Improve Insulin Sensitivity

Insulin resistance is present in 22% or more of horses, depending on breed, and contributes to laminitis in these horses.

Obese horses (body condition score of 8 out of 9) supplemented with short-chain FOS for six weeks had improved insulin sensitivity. This occurred even with no change in body weight or body condition score by the end of the study. [3]

More research is needed to understand how prebiotics support insulin sensitivity in obese horses. It may be related to improved fermentation of simple sugars and starches in the stomach and small intestine so that the glucose loads from the meals were reduced (65% of the calories in the diets used came from grain). Alternatively, there may be hormonal effects from the increased production of volatile fatty acids.

Whatever the mechanism, improving insulin sensitivity is critical to support metabolic health in obese horses and to decrease the risk of laminitis.

Non-obese horses also benefited from prebiotic supplementation using Jerusalem artichoke meal which contains FOS. These horses had improved glucose removal from the blood after a meal, suggesting improved insulin sensitivity. [4]

In lean horses, improving insulin sensitivity can help prevent weight gain and support a healthy metabolism, particularly in the liver and muscle tissue.

4) Improve Digestibility in Senior Horses

Senior horses often experience weight loss or struggle to maintain their weight. Improving digestive function and nutrient assimilation might help support weight management in these horses.

On control diets without prebiotics, senior horses (>23 years of age) had lower dry matter, energy, and fibre dige