How Is an Equine Digestibility Trial Conducted?By Kentucky Equine Research Staff · December 12, 2017
Just because a horse eats something doesn’t necessarily mean the nutrients are digested and used for energy or body maintenance. In fact, a large amount of indigestible fiber is part of the average horse’s diet. However, other feedstuffs, particularly grain, are fed to provide necessary nutrients.
At Kentucky Equine Research, some studies are designed to quantify the amount of a particular nutrient that is actually absorbed from ingested grass, hay, grain, or dietary supplements. To conduct this type of in vivo (involving live animals) research, horses are fed an experimental diet. The horses are stalled individually but allowed access to turnout, either in a drylot or while wearing muzzles to prevent grazing.
Collection periods are integrated into each trial, with each period consisting of a dietary adjustment period (usually 14 or 21 days) and a five-day urine and feces or feces-only collection period. Waste products are analyzed to determine the amount of a particular nutrient that passes though the horse’s body without being absorbed. By comparing this figure with the precise amount that was fed, it is possible to calculate the exact degree of digestibility of that nutrient.