Horse Digestive Supplements: A Guide to Your Horse's Gut

A horse digestive supplement is a complementary feed that supports normal digestive function, usually with ingredients such as live yeast, yeast-derived prebiotics and amino acids. The biggest influence on your horse's digestion, though, is how it is fed. This guide covers both: how the equine digestive system works, the feeding habits that matter most, and what to look for in a supplement.

How a horse's digestive system works

Horses evolved to graze for most of the day, eating small amounts of fibrous plants almost continuously. Their stomach is small for their size, and it produces acid all the time, whether or not the horse is eating. Chewing forage produces saliva, which helps buffer that acid.

Most fibre is digested further along, in the hindgut: the caecum and large colon. There, a large population of microbes ferments fibre into volatile fatty acids, which are a major source of energy for the horse. Those microbes are adapted to the horse's usual diet, which is why sudden changes in feed, or large starchy meals, can upset the balance.

Feeding habits that support normal digestion

• Forage first. Hay, haylage or grass should make up most of the diet. A common guideline is at least 1.5% of bodyweight in forage dry matter a day, which is about 7.5 kg for a 500 kg horse.
• Little and often. Try not to leave your horse more than four to six hours without forage, so its stomach is not left empty.
• Change feeds gradually. Introduce a new hay or hard feed over one to two weeks, mixing the old with the new.
• Keep hard feeds small. Split concentrate feeds into several smaller meals rather than one large one.
• Water and turnout. Constant access to fresh water and as much turnout as is practical are part of a healthy routine.

What goes into a horse digestive supplement

• Live yeast (Saccharomyces cerevisiae) is used in horse feeds as a digestibility enhancer, supporting fibre digestion in the hindgut.
• Prebiotics, such as yeast-derived mannan-rich fractions, are food for the gut's microbes rather than microbes themselves.
• Postbiotics are components and by-products of microbes, such as yeast cell fragments and the compounds produced during fermentation.
• L-glutamine is an amino acid used as fuel by the cells that line the gut.
• Betaine is a nutrient involved in normal cell function and water balance.

As with any supplement, look for clearly declared amounts and a feeding rate by bodyweight, so you know exactly what your horse is getting each day.

When owners use a digestive supplement

Owners often feed a digestive supplement when a horse's routine changes: a move to a new yard, a change of forage or season, travel and competition, or a period of box rest. It supports normal digestive function as part of a balanced diet, but it is not a substitute for the feeding habits above.

When to speak to your vet

Colic is an emergency. Call your vet straight away if your horse is pawing, rolling, looking round at its flanks, sweating, off its food or not passing droppings.

Speak to your vet, too, about ongoing loose droppings, weight loss, a dull coat, girthiness or a change in behaviour at feed time. These can have many causes, including gastric ulcers, and they need a proper diagnosis.

HerdLab Digestive Support

HerdLab Digestive Support is our daily horse digestive supplement. It combines live Saccharomyces cerevisiae CNCM I-4407 with yeast products providing postbiotics and a mannan-rich fraction, betaine HCl, L-glutamine and pumpkin. It is fed at 35 g a day for horses up to 300 kg and 50 g a day for horses over 300 kg, and a 1.5 kg pouch lasts about 30 days at the higher amount. The product page has the full feeding guide and label, or you can browse the full HerdLab range.

Frequently Asked Questions

Can a digestive supplement prevent colic or ulcers?

No. A digestive supplement is a complementary feed that supports normal digestive function. It cannot prevent or treat colic or gastric ulcers. Forage-based feeding, gradual changes and prompt veterinary advice matter most.

How long can I feed a digestive supplement for?

Most digestive supplements, including HerdLab Digestive Support, are designed for daily feeding as part of a balanced diet. Follow the feeding directions on the product you choose.

Should I change my horse's diet at the same time?

Where you can, make one change at a time, and introduce any new feed gradually over one to two weeks.