Fiber is a measure of these specific carbohydrate fractions that exist in pellets as they do in long stem hay. So yes, it is possible to meet a horse’s need for fiber feeding hay pellets. | Photo: Kevin Thompson/The Horse

Q.  I am considering moving my horse to a new barn for the winter because it has a covered arena. However, the barn managers feed hay pellets instead of long-stem hay, and I’m worried my horse will not get enough fiber. Can hay pellets provide enough fiber?

A. Fiber is a vital component of the forages we feed to horses and is necessary for maintaining a healthy hindgut bacterial population. Often considered “filler” thanks to the way fiber is often portrayed in human nutrition, in the horse fiber  is vital for digestive tract health because it’s a necessary source of nutrients for the hindgut bacterial population.

If you search for the definition of fiber, you’ll find that it is a term used to describe a collection of carbohydrates such as cellulose, pectin, and lignin, which are resistant to enzymatic digestion in the small intestine. Because humans don’t have an extensive population of fiber-utilizing bacteria in our large colons, these carbohydrate fractions aren’t as well digested in our digestive tracts as they are in horses’ gastrointestinal tracts—hence the commonly held belief that fiber is just filler. Even in human nutrition we’re learning about fiber’s role in our large colons, its impact on the bacteria that live there, and the far reaching health consequences it might have