10 keys to equine gut health

A horse’s gastrointestinal health begins with not only what he is fed, but how and when he is fed.

A horse’s gastrointestinal (gut) health begins with not only what he is fed, but how and when he is fed. This is where it pays to follow certain “best practices” that help mimic the diet and routine that Mother Nature intended:

• Beef up the turnout: A pasture-kept horse will almost never colic because his digestive system is designed for near-continuous grazing. When fitted with grazing muzzles, horses at risk for laminitis or obesity can also benefit from generous pasture time because they will still be moving around, interacting with others, and eating small amounts frequently—all activities beneficial to digestive health.

Turnout is a key to gut health in horses
A pasture-kept horse will almost never colic because his digestive system is designed for near-continuous grazing. (Getty Images)

• Feed quality hay: Whether it’s orchard grass, timothy or alfalfa, ensure that the hay you offer your horse is free of dust, mold and longer, less-digestible stems, which can cause digestive upset or worse. A good bale of hay will smell fresh when opened up. If your bales contain a lot of “sticks” but looks good otherwise, experiment with feeding a little extra so your horse can work around the parts he doesn’t want.

• Keep food in your horse’s stomach: A stomach that was designed for near-continuous grazing will keep churning up digestive acids whether or not there’s something in it to digest. When the stomach is empty, the result can be gastric ulcers. Saliva helps buffer the stomach acid, and horses produce nearly twice as much saliva eating hay or grass as they do when eating grain. So it makes sense to keep hay in front of horses 24/7, dividing the daily ration into smaller portions fed throughout the day and into the night, as necessary, to prevent wastage. 

• Feed only as much grain as needed: A diet high in forage and low in concentrates is essential to maintaining your horse’s natural digestive balance. Keep in mind that grains (especially sweet feeds) are high in sugars and starches. Excessive intake of sugars and starches can create a microbial imbalance in the hindgut, which is designed to digest primarily grass. The result can be the production of gas, which can lead to discomfort and even colic. Worse, an overload of sugar and starch can precipitate laminitis—the potentially devastating inflammation of the soft tissues within the hoof. While tradition tells us to feed extra grain to older horses, “hard keepers,” broodmares or equine athletes—many of whom require an extra boost to maintain weight—it’s wise to seek professional advice about the safest ways to add calories to your horse’s diet.

• Hay before grain: If you can’t provide continuous access to hay, this feeding rule—which you probably learned in 4-H or Pony Club—still holds true. Why? Because the equine stomach is rather small, and food moves through it rapidly. Given hay, grain and water at the same time, most horses will dive into the grain first, followed by the hay and water. The grain will then go through the stomach and intestine too quickly to be digested thoroughly, possibly causing problems in the hindgut when its sugars and starches arrive there unabsorbed. An appetizer of hay helps slow this process down, so feed your horses their hay, top up their water and wait at least half an hour before following up with grain.

• Provide fresh, clean water: It goes without saying that your horse needs 24/7 access to fresh, clean water that is neither too hot nor too cold—and definitely not frozen (up to 12 gallons per day is the average intake). Feel free to encourage him to drink his fill, even after exercise. This keeps everything he ingests flowing smoothly through his digestive system. Too little water, and an impaction is more likely to form, which can cause serious colic. If you use heated buckets or tanks in the winter, don’t forget to check that these units are properly grounded; use a voltmeter or call in an electrician if necessary. Even the slightest “tingle” of electric current will deter a horse from drinking. 

• Make sure your horse gets exercise: A horse that stays active is likely to have healthier digestive function, because exercise helps stimulate the gut’s smooth muscle contractions. Fortunately, this doesn’t require extended sessions under saddle; just walking around and grazing in the pasture for an hour a day is enough to keep things moving in a horse’s gut better than if he were stuck in a stall. If you want to prevent impactions and gas buildup, ensure that your horse gets plenty of turnout.

• Seek grain alternatives to add calories: If your horse needs to put on a few pounds (or maintain weight during the competition season), make sure he does it in the healthiest of ways. Adding a bit of corn, flax or canola oil to his ration is a safer bet to boost calories than adding more grain. It also adds sheen to the coat and helps protect against ulcers because fat helps keep matter in the stomach longer, which in turn helps control acid levels. Other healthy alternatives to consider adding to your horse’s diet are high-fiber commercial feeds that include the likes of beet pulp or soybean hulls. These more fibrous feedstuffs are lower in starches and sugars than traditional grain feeds and, because they’re digested more like forage, less likely to cause serious gas colic or laminitis.

Guard the gut flora: Microbes—the organisms or “flora” populating a horse’s gut—are essential in the right amounts and the correct balance to help him digest food and absorb nutrients; some are even necessary for creating essential nutrients. However, factors like stress or the introduction of medications such as antibiotics can upset this delicate balance, causing weight loss or chronic diarrhea and even increasing the risk for certain types of colic. This is where probiotics and prebiotics—widely available in supplement form—can help replenish “the good stuff” when it’s needed most.

• Watch out for sand: While ingesting a little dirt while grazing or eating from the ground is normal and usually harmless, horses living in areas with sandy soil run the risk of developing sand colic. Grains of sand ingested during grazing settle in the intestines and, over time, can accumulate to the degree that they block ingesta, leading to painful colic. Preventive measures include minimizing your horse’s exposure to sand, placing hay in a feeder or net, or feeding from a rubber stall mat. You might also consider adding a natural laxative called psyllium (made from the ground seeds of the Plantago plant) to your horse’s diet. Once ingested, psyllium swells, becomes gelatinous and can help push sand through the intestine. You may want to feed a psyllium supplement at home as a preventative, but for horses who already have large accumulations of sand in the colon, research shows daily nasogastric tubing with psyllium and magnesium sulfate (Epsom salts) for three to seven days is a more effective treatment. Your veterinarian can test your horse’s manure for sand and advise you on the best course of action. 

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