As the years pass, we see shifts—both subtle and dramatic—that remind us our horses are aging. Backs sway, muscles atrophy, metabolisms slow or speed, coats develop flecks of gray, and bodies just aren’t as limber as they used to be. Some changes, such as those related to dentition and digestibility, can influence what these horses need in their diets. It’s at this point in a horse’s life that feeding a “senior feed” might become a necessity. Generally, you can tell a feed is formulated for senior horses by both its Association of American Feed Control Officials-regulated product name and its purpose statement. Looking at a feed’s guaranteed analysis and ingredients list can also tell you if it is suited for older horses. In this article we’ll describe some of the physical issues that cause horses’ nutrient needs to change and how a senior feed can meet those requirements.