Essential nutrients must be provided in the horses diet because his body cannot synthesize them or produce them in adequate amounts. | Getty ImagesQ: I often hear the term essential nutrients from equine professionals, but Im not sure what that means or how it affects the way I feed my horse. Can you explain what essential nutrients are and how they should factor into my horses diet?A: Essential nutrients are those we need to provide in a horses diet because his body either cannot synthesize them or cannot produce them in adequate amounts. These nutrients support overall health and help prevent deficiencies.Horses need essential nutrients from six categories: water, carbohydrates, fats, proteins, vitamins, and minerals. Authors of the Nutrient Requirements of Horses, 2007 (NRC) detail the recommended amounts of each essential nutrient to prevent deficiencies, based on the current scientific knowledge.For example, nutritionists consider vitamin E essential because horses cannot synthesize it in the body, so owners need to supply it in the diet. In contrast, vitamin C does not have a defined dietary requirement because horses can synthesize it from glucose, which experts assume meets their needs.Following the NRC guidelines will help ensure your horses diet meets his nutritional needs. However, it can be confusing and overwhelming to calculate these numbers for your horses feed. Luckily, equine nutritionists have already done this work for you.Nutritionists designed commercial feeds from reputable companies to meet these requirements if fed at the manufacturers recommended rates. Ration balancers, performance feeds, and lifestyle feeds can meet your horses nutritional requirements when you feed them alongside adequate forage and salt.Start formulating your horses nutrition program by feeding forage at about 2% of his body weight on a dry matter basis. Then choose a fortified feed to cover any nutritional needs the forage doesnt meet.The type of concentrate feed you choose depends on your horses body condition and workload. For example, a mature horse that readily maintains his weight on forage would be a candidate for a ration balancer. However, a performance horse that is a harder keeper might need a concentrate that also provides supplemental calories. Again, always feed the product at the recommended rate to ensure it meets your horses nutrient requirements. If you feed less than the recommended rate, check the label for instructions on combining it with a ration balancer or consult a qualified equine nutritionist to adjust the diet appropriately.Researchers continue to investigate and define the full range of essential nutrients horses need. For example, horses need amino acids, or the building blocks of protein. There are 21 amino acids, 10 of which are essential. However, researchers have only established a documented requirement for one essential amino acidlysine. Ideally, wed have established a requirement for each of the 10 essential amino acids, but that research has yet to be done.Take-Home MessageTo support your horses health, feed the recommended amount of each essential nutrient daily as described by the NRC based on the current scientific understanding. Feeding adequate forage, providing salt, and offering a commercial feed at the manufacturers recommended rate can effectively meet your horses essential nutrient requirements. An equine nutritionist can also help you balance your horses diet and be sure his needs are met.