A healthy digestive system is crucial to the well-being of any animal and none more so than the horse.

The horse has a delicate digestive system and an imbalance in the gut environment can trigger off all sorts of problems including colic and laminitis, every horse owner’s worst nightmare.

Less obvious effects of poor gut health include impaired performance, compromised immunity and some stable vices, triggered by pain caused by ulcers and acidosis.

Fibre First

In the wild, horses consume fibrous, low energy forages for up to 17 hours a day.

In order to deal with this feeding pattern the horse’s digestive system has evolved to digest large quantities of fibre. The majority of starch, sugars, fats and proteins are digested in the stomach and small intestine.

The stomach is relatively small and digestate passes through the foregut fairly rapidly. It then proceeds into the hindgut where the fibrous fraction is digested by microflora, using the process of hindgut fermentation.

Limited volume

To maintain gut health, the best thing for a horse to eat is forage in the form of grass or preserved grass. Unfortunately, forage does not provide enough energy, protein etc for the hard-working horse. For some breeds that have been in domestication for years, forage does not even provide enough energy for maintenance, let alone work.

The cubes, coarse mixes and cereals we feed to the horse, provide good fuel (starch, sugars, soluble fibre) but only use in moderation. Only small amounts of starch can be digested and absorbed by the foregut.

If a large amount of starch enters the small intestine, the starch digesting enzymes cannot cope and undigested starch will pass into the hindgut. This is when problems occur. Remember that the horse’s stomach is about the size of a rugby ball and an absolute maximum of 2kg of concentrate should be fed in any one meal.

Delicate balance

In the horse’s hindgut billions of microflora exist, these are 'friendly' bacteria or good bugs.

They digest fibre for the horse in return for the provision of an environment in which they can survive. If undigested starch (from the feeding of high levels of concentrates) reaches the hindgut, it will be broken down and lactic acid will be produced. This acid kills off the fibre digesters and inflames the gut wall (colitis).

With fibre digesters depleted, the horse will not be able to digest fibre, the dung will become loose, the inflamed gut wall opens the way for the absorption of toxins into the bloodstream and the reduction in good bacteria allows bad bacteria to proliferate and take over.

Sudden changes in diet, stress, a course of antibiotics and wormers will also upset the gut's microflora balance.

Managing digestive health

There are many things that we can do to help keep the gut healthy.

Management changes can be implemented:

n Assess if your horse really requires high starch concentrates or cereals.

If your horse keeps his condition and has enough energy levels for the job he is doing then he does not require a high starch “competition” feed. Opt for feeds high in fibre and oil instead.

Often a good quality chaff with a vitamin and mineral supplement or an appropriate balancer is all that is required.

n If your horse does require high levels of concentrate make sure you split it into as many meals as possible (remember no more than 2kg per meal). Feed little and often.

Feed along with alfalfa or chaff, this slows down the rate of passage of the feed and further aids digestion of starch.

Again look for products with high oil and fibre levels where possible.

n If you feed straight cereals consider replacing some of it with oil, sugar beet pulp and/or alfalfa.

n Make sure any changes are made gradually, the gut microflora need time to adjust to a different type of feed or amount of feed. It is sometimes helpful to think about the concept of feeding the bugs as well as the horse.

No sudden changes includes the change from hay to haylage or vice-versa at this time of year!

Digestive enhancers

As with most types of supplements for horses there is an array of additives to choose from.

The advice, as always, would be to use products from reputable companies with some research to back up any claims.

The following clarifies what these supplements consist of and the theory behind how they work:

n Prebiotics – These products 'feed' the good bugs, providing them with an energy source, which will help them to proliferate and keep the bad bugs out via competitive exclusion. Most (but not all) prebiotics are carbohydrates and you will see them mentioned as MOS (mannanoligosaccharides) or FOS (fructooligosaccharides). These can be fed on a daily basis as an insurance and will be found in some commercial feeds.

n Probiotics – These are living microflora which promote immunity and efficient digestion. They swell the number of good bacteria, again preventing the bad bacteria from gaining a foothold. These are best used strategically at times of anticipated stress, when giving antibiotics or worming. They should contain high numbers of viable, beneficial microflora. Check with manufacturer or a nutritionist before buying.

n Yea-sacc 1026® – Is a live yeast. It promotes the good bugs, increases digestion of fibre and reduces the effects of lactic acid on the gut lining and good bugs. The stabilising effect of Yea-sacc on hind-gut fermentation means that larger amounts of cereal can be fed.