Vet and equine nutritionist Dr David Wood has examined the importance of fibre in a horse’s diet.
Fibre is even more important for horses than humans because a horse is a herbivore, whose natural diet and digestive system is designed by evolution to eat high fibre foods exclusively.
Dr Wood says logically then, we should feed horses as much grass (or hay, or chaff) as possible and minimize other feeds. As a rule this is true, and will get the best results in terms of health and good digestive efficiency.
However, two factors prevent us from applying that totally natural system.
The first is energy. As soon as you ask the horse to perform work (including exercise or bearing a foal), his/her energy requirements increase, often above the level they can manage to extract from grass alone.
The second factor is grass quality. Even if the grass could provide enough energy, in this country it is very often short on other nutrients like minerals and trace elements.
If the fibre balance in the diet is out of whack, the horse’s whole world gets out of shape.
More information, along with some practical suggestions on how to maintain the balance, can be viewed here.