Carbohydrates, including starches, sugars, and fiber, provide horses with the energy they need to meet their daily requirements. But what type of carbs should you be feeding? High-starch diets, for instance, can increase the risk of metabolic disease, while high-fiber diets might better support horses' nutritional health.

Recently, Danish and Norwegian researchers studied how high-fiber feeds affect horses' nutrient digestibility, feed passage rate, and nitrogen and water balance.

The research team fed four Norwegian Trotter geldings fitted with a cecal cannula (a tube researchers could collect samples from) four energy-equivalent diets. These diets contained enough digestible energy and protein to sustain a 550-kilogram (1,200-pound) horse in light to moderate exercise yet had varying carbohydrate fractions. The diets included:

• Hay only;

• 85% hay and 15% soaked sugar beet pulp (SBP);

• 68% hay and 32% pelleted barley; and

• 68% hay, 26% pelleted barley, and 6% SBP.

To measure each feed's total mean retention time (TMRT), the team added a nondigestable marker called ytterbium to the horses' hay