Feed Digestibility and Energy Level May Increase in Exercised Horses

Exercising horses use more energy than idle horses, and horses that are allowed to move freely around a pasture have a somewhat decreased risk of intestinal impaction compared to equines kept in stalls. To test other effects of motion, researchers in France designed a study to see whether regular exercise could have an effect on how well horses digested the nutrients contained in the forages and concentrates they ate. The study was partially funded by the Waltham Centre for Pet Nutrition.

Eight previously inactive Standardbred horses were used in the study. For three weeks, the horses were fed at a level of 2.1% of body weight on a dry matter basis. Meadow hay accounted for 55% of the diet, with 45% consisting of a pelleted concentrate feed. Fecal samples were collected on the second day of the feeding period, and nutrient digestibility and fermentation parameters were determined. Six of the horses were then put into a five-week training program after which digestibility and fermentation parameters were again analyzed. Measurements for apparent digestibility of dry matter, organic matter, neutral detergent fiber, hemicellulose, and crude protein were higher in exercised horses after the exercise program than before the horses began the program. Levels of fecal volatile fatty acids and concentrations of acetate and propionate were also higher after the exercise program. Body condition scores and body weights did not change for any of the horses in the trial.

Prior research has shown increased nutrient digestibility in trained endurance horses, and the similar results shown by this study indicate that exercise can improve nutrient digestibility of feeds in horses of other breeds performing a different type of exercise. In particular, the researchers suggested that training at a low intensity could increase hindgut production of volatile fatty acids, thus contributing to the horse’s energy supply.