The horse’s diet has evolved over the years due to the way in which they have had to look for food, water and shelter. Horses are known as nomadic gregarious herbivores. Which means they move around in herds for safety, eating grass and other roughage they can find on their journey to find the sparse food, water and shelter that they would of needed in the wild.

We have the ten golden rules of feeding that can help us to keep the horse healthy and not cause any unwanted issues like colic. These rules are:
Feed according to height, size and temperament.
Feed according to the work schedule
Feed using clean utensils as the horse is a fussy feeder.
Make sure the horse has access to plenty of water throughout the day.
Make changes to the feed gradually as it takes time for the gut bacteria to change.
Always feed high quality feed stuffs as the horse is a fussy feeder.
Feed something succulent every day.
Keep the same feeding times each day as horse are a creature of habit.
Do not exercise directly after feeding as the horses stomach lies directly against the lungs.
Feed plenty of roughage in the horse diet.

These rules have come together over years of experienced horsemen learning about their horses and as you can see the last rule is feed plenty of roughage. Even though there might not have been some much technology around in earlier years, therefore the understanding of the science behind the practice, our forefathers understood how to look after their horses and keep them healthy.

The horse’s gut has evolved to rely on the energy of food from the microbes in the hind gut formatting the masticated cellulose rich fibres in an extra-large caecum and colon. This now occupies a larger abdomen and is suspended from a functionally rigid spine.

When the food passes down through the horse’s mouth it starts the process of being broken down. The tongue and teeth start to break down the grass, hay and forage and it becomes a bulbus that moves down the oesophagus, through the cardiac value into the stomach.

The stomach is a j-shaped organ that sits to the left of the mid-line and in behind the diaphragm and the liver. Once in the stomach the food is broken down even more and passes through the four sections of the stomach. As the food passes out of the stomach it passes though the pyloric sphincter into the small intestine.

The small intestine consists of the duodenum which is a small portion quiet closely attached to the stomach and it encloses the pancreas in one bend of the serosal wall which is where the pancreatic and bile ducts disgorge their products through the ducts in the wall.

The jejunum is the major portion of the small intestine followed by the ileum. In the small intestine the sugars get broken down into starches and glucose, proteins into amino acids, triglycerides into fatty acid and glycerol. Also, vitamins and minerals are prepared for transportation through the mucosal wall.

As the substance moves through the different areas where it breaks down to become chyme. This then moves onto the large intestine which unlike some other herbivores, the equine organs of microbial fermentation of the cellulose content of the diet are in the distal (back) part of the digestive system. This is why the caecum is much larger than that of other single-stomach non-herbivores.

The caecum is a cul-de-sac, comma-shaped and lies downwards to the ride side of the horse. The ileum opens directly into the base, through a muscular value. It is here that all the fibre gets broken down by the heavy populated microbial flora and liberate volatile fatty acids. They are absorbed into the various capillaries of the mucosa, along with the B vitamins produced in the caecum and amino acids and other vitamins not absorbed from the small intestine.

It is because of this process that we need to make sure that the horse is never fed less that 50% roughage within its diet. In fact, if would be better to not go over the 40% concentrate to 60% roughage stage as this will make sure that the digestive system is working and able to keep the food moving through the entirety of the system.

Roughage – Concentrate Ratios.

A chart showing Diet related to the work for a pony of approximately 14.2 hh.

The diagram (from the Pony Club Manual of Horsemanship) shows how much roughage can be used at the different stages of work. The percentage of the total amount of food per day is on the left and the type of work is along the bottom of the chart.

So, when in Medium work your horse or pony will get 30% concentrates (nuts, mix etc.) and 70% roughage. We can work out the different types of work a horse or pony are in as follows:

Maintenance – This is where the horse is able to remain healthy and maintain all bodily functions, such as eating, breathing, keeping warm, growing, a summer or winter coat, or repairing any injuries. Any working horse or pony who is put out to grass for a break from routine work will e living at maintenance level.

Light work – Maintenance plus up to one hours’ hacking daily, mostly working at walk or trot and very little cantering.

Medium work – Maintenance plus an average of one and a half hour’s hacking daily, with active work which might include cantering, jumping. Lessons or competing at shows.

Hard Work – Maintenance plus final fitness programme for participation in:
Training camps
Team chasing
One day horse trials
Long distance training

Very Hard work – Maintenance plus preparations for Point-to-Point, Three Day Eventing and Long Distance Competions.

This will hopefully give you more of an idea as to why we need to have roughage in the diet and the different types of work that a horse or pony might have to do and therefore need to keep their gut healthy.

References: The Manual of Horsemanship – The Pony Club
The BHS Veterinary Manual Second Edition.

Article by Sam Goss BHSI/PCCHL5. MSc Coaching Science
Tel: 07875 311983