Understanding Digestive Health
By Dr Clarissa Brown-Douglas
The importance of nutrition for the equine athlete is undeniable. Without well-balanced diets, horses cannot perform, and without a well-functioning gastrointestinal tract, horses cannot adequately transform diets to performance fuel. All too often we focus on what we feed, but equally important for gut health is how we feed, so here are a few points to remember for various areas of the gut.
Stomach
The horse’s stomach is relatively small, accommodating only 7.5 to 15 litres of ingesta, which is markedly less than the stomachs of similar-sized animals. Stomach volume dictates meal size, so horses are therefore incapable of efficiently processing large meals.
A medley of gastric enzymes and acids are secreted by the stomach. These acidic liquids are incredibly efficient at further breaking down feeds and preparing nutrients for absorption.
The constant acid production can be a menace to performance horses, especially those that are stabled for long periods of time without free-choice access to pasture or hay. Regular forage consumption supports stomach health in two ways: the constant flow of saliva that lubricates feed for chewing and swallowing aids in reducing acidity of the stomach, and fibre in the stomach gives the acid an appropriate outlet on which to work, saving the delicate stomach lining from erosion and the eventual formation of ulcers.
Gastric ulcers in the squamous or upper region of the stomach are a well-known source of problems for performance horses. Though these lesions affect horses differently, it is not uncommon for horses to be sour and unwilling to work, experiencing a noticeable decline in performance. Clinical signs might include loss of weight, girthiness, dull coat, and lethargy.
Management tip: Provide horses with forage at all times. Quality of forage depends on the horse. A good doer might need lower-quality hay or pasture, but a hard-keeper may require a high-quality variety. Calorie-rich lucerne has inherent buffering properties, so it would be especially appropriate for a hard keeper prone to gastric ulcers. If forage cannot be available at all times, take precautions to prevent gastric ulcers by using a supplement that contains a buffering agent. Neigh-Lox® contains a research-proven blend of slow and fast acting antacids as well as coating agents which can protect the sensitive stomach lining from the burning action of stomach acid. Neigh-Lox is highly recommended for all horses at risk of gastric ulcers.
Lesions in the lower, glandular region (EGGD) are less understood but are a concern in performance horses, especially warmbloods. EGGD appears to be more closely linked to exercise management, heavy workload, and stress, rather than nutrition, with horses in full work with limited rest days and those actively competing being more susceptible. Traditional EGUS treatment has inconsistent results in EGGD horses. Current treatment strategies for EGGD include the use of sucralfate, a long-acting shielding agent which binds to ulcerated areas of the stomach protecting it from gastric acid, as well as workload management. There are limited nutritional links to EGGD, however because EGGD is an inflammatory disease, it would be prudent to supplement horses in heavy work with anti-inflammatory compounds such as long chain omega 3 fatty acids DHA and EPA. There has also been some recent research published which positively links increased levels of lucerne in the diet with lower rates of EGGD. EO3® is the only equine supplement on the market with high concentrations of long chain omega 3 fats DHS and EPA and is highly recommended for horses at risk of inflammatory conditions. Sucralox® is a veterinary-only sucralfate-based supplement which also includes a yeast derivative and buffering agents and is designed as a supplement for horses with or at risk of glandular ulcers.
Hindgut
The hindgut is a collective term for the cecum and the colon. The cecum is the epicentre of forage digestion, due to the fermentation capability of the billions of microorganisms that reside there. Digestion of fibre results in the production of energy that is vital for fuelling everyday work and play. Fibre digestion by the microbial population continues on through the colon, particularly in the areas that are most capacious.
There are times, though, that the cecum does not function at full capacity. Among performance horses, one of the likeliest causes is hindgut acidosis. Because performance horses must often eat rations containing large volumes of cereal grain, starch sometimes passes through the small intestine undigested. Unfortunately, the cecum is not the best place for starch digestion. When cecal microorganisms ferment starch, the environment changes considerably, becoming increasingly acidic. With the swell in acidity, a population shift occurs among the microorganisms, with many beneficial species dying off.
An unstable microbial population sometimes causes problems with weight loss, reluctance to eat, poor performance, recurrent low-grade colic, loose manure, and behavioural issues.
Management tip: Feed small meals, no larger than 2.5kg, so starch digestion is complete by the time ingesta enters the cecum. It is not unusual for horses to be fed three or more small meals a day when large quantities of feed are necessary to maintain body condition and meet energy requirements.
Management tip: Lower the risk of undigested starch entering the hindgut by choosing a feed that is higher in fat and fibre, or by selecting a feed that contains grains that have been cooked (steam-flaked, micronised, pelleted, or extruded), which have higher prececal digestibility.
Management tip: In addition to high-grain diets, hindgut acidosis can be caused by fructan-rich pastures. The same mechanism is at work: the small intestine becomes overwhelmed with fructans and is unable to properly process it, and the undigested fructan moves on to the cecum, where fermentation causes a downshift in pH and subsequent upset of the microbiome.
Management tip: A hindgut buffer can help moderate drastic swings in the acidity of the hindgut. The buffer should be encapsulated, so it is not released until it enters the cecum of the horse, exactly where it’s needed. EquiShure® is an encapsulated and protected hind gut buffer which releases in the large intestine. It is research-proven to buffer acidic conditions cause by starch or fructan overload and increase the pH to optimal levels for fibre digestion and general microbiome health.
Management tip: Horses at risk of gastric ulcers and hind gut acidosis may benefit from a total digestive tract buffer. Triacton contains a blend of ingredients including KER BMC™, which is research proven to buffer gastric and hind gut acid. Triacton also contains a yeast metabolite, which supports fibre digestion and promotes a healthy microbiome.
In summary, digestive health is becoming front and foremost in horse owner’s minds, and for good reason – the equine digestive tract is vital for horse’s health, well-being and performance. How we feed our horses is key to ensuring the gut remains healthy including adequate forage, small meals, reduced reliance on cereal grains, and providing digestive support supplements where appropriate. There are a ton of “digestive health” supplements on the market, so do your research!! Remember that KER Targeted Nutrition supplements are scientifically-proven and evidence based.
