Types of Grain

Walk into a feed store and the grain aisle presents a bewildering array of options. Whole oats. Cracked corn. Barley. Pelleted complete feeds. Sweet feeds loaded with molasses. Textured feeds with visible oats and grains mixed with processed ingredients. The variety exists because different horses have different nutritional needs, and different grains offer different nutritional profiles. Yet most horse owners select grain based on habit, price, or what the previous owner fed, without understanding what they're actually feeding or why.

Grain serves a specific purpose in horse nutrition: concentrated energy. A horse can survive and thrive on good pasture or quality hay without any grain. Grain becomes necessary when a horse has high energy demands that forage alone cannot meet—hard work, performance demands, weight loss that won't resolve through forage alone, or metabolic situations where concentrated nutrition becomes necessary. Understanding this baseline—that grain is a tool for specific situations, not a required component of every horse's diet—is fundamental to understanding grain selection.

The confusion around grain selection stems partly from the way grain is marketed. Feed companies sell grain primarily to horses that don't need it. A pleasure horse that's overweight already receives marketing for sweet feeds and pelleted supplements designed to add calories. A metabolically sensitive horse prone to laminitis receives the same marketing. The market assumes horses need grain because that's how they sell volume, not because it's nutritionally correct for most horses.

Different grains offer different nutritional characteristics. Oats are relatively cool energy—they provide calories and some protein without creating the metabolic heat that other grains produce. Corn is energy-dense and efficient but creates more metabolic heat and has less protein. Barley is in between. Pelleted feeds can be anything inside the pellet, from simple grain mixtures to complete nutritional solutions designed to replace hay and grain combined. Understanding these differences allows intelligent selection rather than accepting whatever the feed store has on sale.

This guide covers the major grain types horses eat, what each offers nutritionally, why you might choose one grain over another, and the common mistakes made when selecting grain for specific horses. You'll learn that most horses eat grain they don't need, and how to evaluate whether your horse should be eating grain at all.

Oats represent the most commonly fed grain and the most common grain people think is appropriate for horses. Oats provide roughly 70 calories per ounce depending on the specific variety. They contain about 12% protein, which is modest for grain but adequate for most purposes. The reality that makes oats attractive is that they're considered a relatively cool grain, meaning they don't create the metabolic disruption and heat production that other high-energy grains produce. A horse can be fed oats without the same concern about excitability or metabolic stress as with other grains.

Whole oats are digestible because horses have molars effective at cracking the oat hull. Horses eating whole oats efficiently extract the nutritional value without requiring processing. This matters because it means you're not paying for processing the grain adds little additional value. Some horses don't crack oats effectively—very young or very old horses with dental issues—and these horses benefit from rolled or crimped oats that have been physically processed to make cracking unnecessary.

Corn provides nearly 100 calories per ounce depending on moisture and storage, making it significantly more energy-dense than oats. Corn is carbohydrate-rich but lower in protein than oats. This makes corn suitable for horses that need serious caloric density—hard-working horses that need maximum calories in minimum volume. However, corn is considered a hotter grain, producing more metabolic energy and heat production. Horses fed high amounts of corn sometimes develop behavioral issues related to excess energy or metabolic stress. For some horses, that extra heat production becomes problematic.

Barley provides energy between oats and corn nutritionally—roughly 80 calories per ounce with higher protein content than corn but comparable to oats. Barley is often overlooked and less commonly fed than oats or corn. It's nutritionally adequate but doesn't offer obvious advantages over oats or corn for most situations. The main argument for barley is that its moderate characteristics might suit horses that need more energy than oats provide but less heat production than corn creates.

Pelleted and textured grains vary enormously in composition depending on what they contain. A pelleted grain might be pure oats pressed into pellets, or it might be a complex mixture of multiple grains, supplements, medications, and processed ingredients all combined into one convenient product. Reading the ingredient list is essential because the name gives no indication of content. A pelleted sweet feed might contain more molasses than actual grain, or a pelleted complete feed might be designed to replace both grain and hay. Without reading ingredients, you're essentially guessing what you're feeding.

Sugar content matters for certain horses and often exceeds what people realize. Whole grains contain natural sugars but in modest amounts. Sweet feeds and complete feeds often contain added molasses or other sweeteners that elevate sugar content significantly. A feed marketed as a performance grain might contain 15-20% sugar from molasses additions. For horses with metabolic sensitivity, insulin resistance, or laminitis risk, these feeds become problematic because the sugar content drives metabolic dysfunction.

The foundational guideline for grain feeding is this: feed only what your horse actually needs. Before selecting a grain, determine whether your horse needs grain at all. A horse maintaining weight on quality pasture or hay doesn't need grain. A horse maintaining weight on good hay doesn't need grain. The only situations where grain becomes necessary are: hard work requiring more calories than forage provides, weight loss requiring concentrated calories for recovery, or metabolic situations where specific grain types support health.

The quantity of grain should be calculated based on your horse's body weight and work level. A rough guideline is feeding 0.5-1% of body weight in grain for horses with moderate work demands. A 1,000-pound horse in moderate work would receive 5-10 pounds of grain daily split into multiple feedings. A 1,000-pound horse in hard work might receive 10-15 pounds daily. A 1,000-pound pleasure horse shouldn't receive any grain unless weight loss indicates it's needed.

Feed grain in multiple small meals rather than one large feeding. A horse's digestive capacity for grain is limited—roughly 4-5 pounds at a feeding is the maximum amount that digests efficiently. More than that overwhelms the small intestine and can cause colic or other digestive upset. Feeding 8 pounds of grain once daily is problematic; feeding 4 pounds twice daily is significantly better. If a horse needs more grain than can be effectively digested in two feedings, increase the number of feedings rather than the volume per feeding.

Introduce grain changes gradually over 10-14 days. Switching a horse from one grain to another abruptly can cause digestive upset or impaction colic. When introducing new grain or increasing grain quantity, mix the new grain with the previous grain in gradually increasing ratios. Day 1 might be 25% new and 75% old. After a few days, move to 50/50. Gradually transition to the new grain over roughly two weeks. This slow transition allows the bacteria in the horse's cecum and large intestine to adapt to the new feed composition.

Store grain in rodent-proof containers in a dry location. Moldy grain is dangerous because it contains mycotoxins that cause serious health problems. Grain stored in damp conditions develops mold quickly. Use airtight containers if possible, and feed grain that was purchased months ago carefully—old grain loses nutritional value and can develop mold even in storage. For horses with metabolic sensitivities, store grain in a way that prevents accidental overfeeding during turnover or refilling.

Different horses require different grain selections based on their work level, metabolism, dental status, and health. Understanding these differences prevents feeding inappropriate grain to horses that shouldn't be eating it at all.

Hard-working horses doing serious training, competition, or ranch work need substantial grain because forage alone doesn't provide enough calories for recovery and maintenance. These horses benefit from energy-dense grains like corn or high-calorie grain mixtures. The high work level metabolizes the grain without excessive heat production becoming problematic. A barrel horse in serious training or a dressage horse in intensive preparation can handle corn's metabolic heat because the work burns the energy. These horses need grain; the question is simply which grain provides adequate calories most efficiently.

Pleasure and light-work horses rarely need grain. A horse ridden three times weekly at walk-trot doesn't have energy demands exceeding what quality hay provides. Adding grain to a pleasure horse often creates excess calories that contribute to weight gain, metabolic dysfunction, and behavioral issues. These horses don't benefit from grain; they benefit from appropriate hay quantity and quality. A common mistake is feeding grain to pleasure horses because the owner assumes all horses need it.

Metabolically sensitive horses and horses with Equine Metabolic Syndrome require special grain selection. These horses shouldn't eat sweet feeds, molasses-containing grains, or high-corn rations. Instead, they need low-sugar grain options—straight oats, or specialized grain formulations specifically designed for metabolic horses with sugar content below 10%. Some metabolic horses don't need grain at all and thrive better on hay alone with specific vitamin and mineral supplementation. Before selecting grain for a metabolic horse, evaluate whether grain is necessary at all.

Senior horses with dental issues often struggle with whole grains. An older horse without effective molars can't crack whole oats and either leaves them largely undigested or chokes attempting to process them. Senior horses benefit from rolled or crimped grains, or complete pelleted feeds designed for senior horses that don't require extensive chewing. Some senior horses with severe dental issues benefit from soaked or steamed grain that becomes soft enough to eat and digest effectively.

Young growing horses have different nutritional needs than adults. Foals and weanlings benefit from higher protein grain than mature horses because they're building muscle and bone. Young growing horses under three years old might receive grain specifically formulated for growth with adequate calcium, phosphorus, and protein ratios that support skeletal development. Feeding adult grain to growing horses creates imbalanced mineral ratios that interfere with proper bone development.

Colic represents the most immediately dangerous problem caused by improper grain feeding. A horse given large quantities of grain at one feeding, or a horse switched abruptly to new grain, develops impaction colic within hours. The cecum and large intestine become obstructed because the grain fermentation and digestion overwhelm the system's capacity. Colic from grain feeding is often severe and sometimes fatal.

Laminitis can develop in horses fed inappropriate grain, particularly horses with metabolic sensitivity fed high-sugar or high-carbohydrate grains. The metabolic disruption from excess sugar causes insulin dysregulation and founder. The connection isn't always obvious—laminitis appears weeks after grain feeding becomes excessive—but the causal relationship is direct. A metabolic horse fed sweet feed daily develops laminitis from the accumulated metabolic stress.

Weight gain and obesity develop from overfeeding grain to horses that don't need it. A horse shouldn't be eating grain unless it's losing weight or has high work demands. A pleasure horse gaining weight on hay plus grain is being overfed. The excess calories store as fat, creating metabolic stress and joint problems. Many overweight horses are overfed grain that their owners believe is necessary.

Behavioral problems sometimes escalate from excessive grain feeding. A horse fed high-calorie or high-heat-producing grain might develop behavioral issues—spookiness, aggression, or hyperactivity. This is particularly common in young horses or horses with naturally high-strung temperaments. Some horses genuinely become unmanageable when fed too much grain because the metabolic energy exceeds their ability to channel it appropriately.

Digestive problems beyond colic can develop from grain feeding. A horse eating moldy grain develops mycotoxin poisoning with subtle signs—reduced appetite, performance decline, or general malaise. A horse switched abruptly to new grain develops gas colic or diarrhea even if it doesn't impaction colic. A horse fed grain in quantities larger than 4-5 pounds per feeding experiences incomplete digestion in the small intestine and large intestine dysfunction.

The most practical tip is to baseline your horse's condition without grain, then add grain only if needed. Many horses thrive on quality hay and pasture without any grain. If your horse maintains good weight, has good energy for work, and performs well, grain probably isn't necessary. Adding grain to a horse that doesn't need it creates problems without benefits.

If your horse needs grain, select based on work level and metabolic status, not on habit or what was previously fed. A hard-working horse can eat corn or high-energy grain. A pleasure horse doesn't need grain at all. A metabolic horse needs low-sugar oats or specialized metabolic grain. These different requirements mean different horses need different grains.

Feed grain in the smallest amount that meets your horse's nutritional needs. A horse needing 10 pounds of grain daily is better managed with 5 pounds twice daily than 10 pounds once daily. If your horse needs more grain than can be fed safely in multiple feedings, reconsider whether that horse's work level justifies that much grain, or whether a higher-calorie forage would be more appropriate.

Read grain labels and know what you're feeding. The name tells you almost nothing. A sweet feed might be mostly molasses. A complete feed might be designed to replace hay. A performance grain might be inappropriate for metabolic horses. Knowing the actual contents allows intelligent selection rather than guessing based on marketing.

Cost should not be your primary selection criterion. The cheapest grain at the feed store often has reasons for being cheap—lower quality ingredients, less processing, or formulation for horses that don't need high quality. For horses needing grain, selecting based on your horse's actual requirements produces better results than selecting based on sale prices. A horse fed inappropriate cheap grain costs more in the long run through health problems than one fed appropriate grain from the start.