Forage is the most natural equine feed and should be the foundation of every horse’s diet. But sporthorses who participate in more demanding disciplines or those who have heavy competition schedules may have different needs when it comes to balancing their diet.

Shannon Pratt Phillips, M.S., Ph.D., PAS, DPL-ACAS Nutrition, Professor of Animal Science, Equine Nutrition and Physiology, North Carolina State University, explains that forages include long-stemmed plant material such as pasture and hay, as well as haylage, hay cubes, chopped hay and more. “Forages are the most important part of a horse’s diet because they provide the bulk of necessary nutrition,” she said.

“It takes horses awhile to eat the long-stemmed plant material in hay, pasture or haylage, which is good for their well-being and behavior; they don’t get as bored,” said Phillips. Since forage takes time for horses to consume, she notes that it also aids in saliva production. “Saliva contains bicarbonate, which can potentially counteract acidity in the stomach. If a horse has issues with ulcers, forage can be very helpful,” she added.

After passing through the stomach, forage moves into the large intestines and colon, keeping them healthy and functioning properly. “Forage, or roughage, keeps things moving in the gut,” Phillips said. “If horses don’t get enough forage, they are more prone to colic, ulcers and other digestive problems.” 

Forage is broken down into two basic types—grasses and legumes. Grasses include orchardgrass, timothy, bluegrass, Bermudagrass and fescue, while legumes are primarily clover and alfalfa. “Clover is beneficial in a pasture, whereas alfalfa is usually better for horses when cut and fed as hay,” said Phillips.

Legumes generally have more protein and calcium than grasses. “Most sporthorses don’t need 100% alfalfa because it contains too much protein and calcium,” Phillips noted. Excess protein takes more energy for a horse to break it down, while too much calcium disrupts the calcium-phosphorus balance in the diet. “Feeding a mix might be more appropriate, depending on the horse, but a good-quality grass hay will usually do fine,” she added.

The nutritional value of hay depends largely on the plant species and their maturity. “If hay is cut when immature and still growing, it will have higher nutritional density than older, more mature and stemmy hay,” said Phillips. “Examine your hay to identify the plants and assess how mature they are—with immature hay being green with more leaves—and what the seed heads look like in mature hay.” You can tell if alfalfa has bloomed and is more mature if you see small purple flowers—or if it’s even older and the blooms have turned to seeds. With timothy, you can see the long seed heads.

While a plant’s maturity can give you some insight, hay analysis allows you to take a closer look into its nutritional value. “It’s impossible to know how much protein or calories are in hay just by looking at it, even if you know its 60% alfalfa and 40% timothy,” Phillips said. “The only way to really know is to get it analyzed.” 

Feeding Forage to Sporthorses

Brian Nielsen, Ph.D., PAS, DPL-ACAN, Professor of Equine Exercise Physiology at Michigan State University and an equine nutritionist who owns racehorses, explains that sporthorses are frequently kept in stalls rather than on pasture, limiting their access to nutrients in fresh grass. “We provide hay because they can’t be out on pasture,” he said. “Ideally, you want to provide as many of the necessary nutrients as possible from forage.”

People often assume elite athletes like sporthorses need high-grain diets. While Nielsen says there may be some truth to that, depending on the individual horse, he still emphasizes the importance of forage and notes that many sporthorses do very well on high-forage diets.“Some people think you can’t meet all of a horse’s caloric requirements from pasture,” he said. “But often you can if it is lush, green pasture.”

Nielsen notes a 2017 Swedish University of Agricultural Sciences study found that a forage-only diet in 2- and 3-year-old Standardbreds didn’t negatively affect their ability to qualify and race before the age of 4. Also, an Australian nutritionist has begun similar work with Thoroughbred racehorses, finding promising results with high-forage diets opposed to high-grain diets.

During a presentation at the 2025 European Equine Health and Nutrition Congress in the Netherlands, Nielsen learned that it’s beneficial when more acetate is produced during digestion, as a horse digests forages in the hindgut. The more acetate produced, the more metabolic acidosis (or too much acid in the body) is delayed. “On a high-forage diet, a horse produces more acetate,” he explained. “Delaying metabolic acidosis could improve performance by delaying the onset of fatigue.”

A high-forage diet is important for sporthorses, and green pasture is often a good choice compared to hay that’s been stored or is low in nutrients. But Nielsen notes that green pasture is very high in some soluble carbohydrates. “It might not be good for horses with metabolic problems, but can be wonderful for sporthorses because it provides the energy they need,” he said. “Horses in the Swedish study were fed haylage, which is full of soluble carbohydrates compared with hay that’s been dried and stored. The horses in Australia were fed good hay, with a high-nutrient content.”

Selecting Forage for a Sporthorse’s Specific Needs 

It is important to select the right kind of forage for the individual. For sporthorses, it must provide adequate energy and contain a reasonable amount of protein. “Horses don’t actually have a requirement for protein. The National Research Council Nutrient Requirements of Horses guidelines give one, but what horses really need are amino acids—that make up the protein,” Nielsen said. “A certain feed might contain a lot of protein but if it is deficient in some of the limiting amino acids, the horse may not be able to utilize the protein.”

If your horse is on pasture, it will be difficult to determine exactly how much he’s eating, but you can tell if he’s maintaining proper weight, so keeping track of his body score is crucial. “Not every pasture is suitable to keep weight on and provide enough of the nutrient requirements for hardworking horses,” he said. “Even when horses are on good pasture, you may need to provide supplemental forage like hay. We can’t just assume everything will be fine if they have unlimited forage.”

Nielsen recommends feeding hay that contains some legumes, but this can depend on the forages available in your region. “If there’s some alfalfa in the hay, however, it will usually improve protein quality and provide plenty of calcium and most other minerals,” he said. “Many grass hays are also fine, but some are not. This is why it is important to have hay analyzed.”

Certain circumstances can sometimes prevent horse owners from obtaining their preferred hay. If your area is in severe drought or wildfires impact agricultural lands and hay crops are short, hay supplies may be scarce and very expensive. While hay alternatives are an option during those times, Nielsen suggests sticking with hay if possible. “Hay cubes may be recommended in times of drought or when you might have trouble finding affordable, good hay. This might sound reasonable on the surface, but do the math,” he advised. “Hay might be expensive, but if you price what it costs on a per-pound basis and compare it to the cost of hay cubes or other alternatives, you are generally better off to pay the high price for quality hay that your horse is familiar with and performs well on.”

Nielsen notes that hay cubes are an acceptable option for older horses with dental issues who are unable to chew hay. “But for a young, healthy sporthorse with good teeth, the hay may still be a better buy,” he said.

Changing Forages 

If you change forages, such as different cuttings of hay with different maturity or switch from hay to pasture, it’s important to gradually transition your horse to the new variety. “The microbial population in the hindgut can be disrupted if you make transitions too quickly,” Nielsen explained. He suggests the following plan for making a forage change:

Day 1: 25% new hay and 75% original hay
Day 2: 50% new hay and 50% original hay
Day 3: 75% new hay and 25% original hay 
Day 4: 100% new hay 

“Or you can even take a little more time to gradually switch,” Nielsen said. 

While it’s ideal to bring your own hay to horse shows, that may not always be possible. If you need to feed hay you purchase at a show, Phillips suggests mixing in hay products, such as chopped hay, to help reduce the variation in hay when traveling since the products are fairly similar bag to bag. “Bring as much of your own long-stemmed hay as you can, but it might be helpful to augment it at home or at shows with some chopped hay since it might be more consistent,” she said. Another suggestion from Phillips is to ask the show facility if they can provide a hay analysis so you can plan accordingly based on the hay that your horse eats at home and the hay available for purchase onsite. 

Your horse might do well on pasture, but if you suddenly take him off pasture and feed hay when you’re competing, this alters his diet significantly. “If you show often and your horse only gets pasture periodically while competing, you don’t want pasture to be the main component of the diet when he’s home, even though he’d be happier on pasture,” said Phillips.

In this situation, she recommends feeding hay to your horse in the barn and only offering him pasture as an extra treat. You also might consider using a grazing muzzle so he can still enjoy being turned out and eat quite a bit of grass without gorging himself. 

When Forage Isn’t Enough

It’s also important to consider what you supplement your horse’s hay with to ensure his diet is balanced. “If you have excellent quality hay and your horse is a hunter with lower energy requirements than a show jumper or eventer, you could potentially meet all of his calorie requirements with just excellent quality hay,” Phillips said. “It all depends on the hay quality.” While good hay can meet almost all of your horse’s nutrient requirements, he might need a vitamin supplement containing trace minerals and vitamins A and E, which tend to be higher in green pasture and lower in dry hay. If he needs additional protein, a ration balancer can provide those key vitamins and minerals, as well as protein. 

For horses with higher energy requirements, Phillips says feeding a concentrated energy mix is likely beneficial. “There are many thoughts about which types of concentrates are better for which horses. Some do better with higher amounts of fat, and others do better with higher amounts of sugar; it often depends on what the horse is doing,” she said. “Those decisions should be made based on what the forage provides.” 

Rather than going with a cookie-cutter feeding plan for your horse, Phillips suggests taking a more in-depth look. “I make a graph to see what the hay covers and see what gaps I need to fill as opposed to just deciding to feed four pounds of a certain feed every day and tossing some hay to that horse,” she said. 

Each horse is an individual and has different needs. One horse might lose weight on the same diet that another horse stays fit on and keeps ideal weight. It’s important to know your horse and monitor his body condition, fitness and overall well-being. If you think you need to make a change to your horse’s diet, work with your veterinarian or an equine nutritionist to discuss your concerns and set up your horse with a diet that is ideal for him. 

For More:

• Read more about selecting the right hay for your horse here.
• To learn more about proper nutrition for sporthorses, click here.

This article originally appeared in the summer 2025 issue of Practical Horseman.