As a horse owner you will be aware that on a freezing cold day, you can warm your hands by pushing them deep inside a horse’s coat, or under their rug. But do you know why?

The heat you feel has actually been produced from inside the horse’s digestive tract, which has been powered by fermentation. So, yes it’s true, a horse does have its own little central heating system. And, you the owner, can keep this flowing by providing the correct material, and for your horse, this means fibre.

As it is digested slowly, fibre causes microbial fermentation, which in turn, automatically creates heat - heat that is sustained for a long period of time.

The calories obtained from fats and grains, can also help a horse stay warm but will not produce sustained heat and will, therefore, be used whenever the horse needs it, whether it’s keeping warm or during exercise.

Tip: If your horse has cold ears then the rest of him will probably be cold too!

Your horse’s digestive system has adapted over time to support the fact that he grazes for many hours per day. Horses have enlarged large and small colons which act as fermentation barrels for the microbial organisms living there. Therefore, if fibre is not provided as part of their diet, these organisms can die and release toxins.

Forages provide large amounts of fibre, which when broken down by these organisms release volatile fatty acids – acetate, propionate and butyrate. Acetate and butyrate can, upon absorption, be immediately used for energy or converted to fat for storage. Propionate can be converted to glucose or also converted into stored fat. Horses consuming high forage diets are provided with substantial amounts of energy, and when fermented by microbes, the fibre releases heat and gasses as a by-product.

So, in summary, your horse needs good quality fibre for optimal health. If long-stem hay or well-maintained pasture is not available, then quality hay, haylage or beet pulp can be fed to increase intake. Forage sources, although lower in digestible energy than higher starch concentrates such as corn or oats, they can provide all the energy necessary.