Understanding How Horses Were Built to Eat
Before we get into the specifics of what to feed your horse, it helps to understand how their digestive system actually works - because it's pretty different from ours, and it explains a lot of the feeding rules that might seem arbitrary.
Horses are hindgut fermenters. That means the bulk of their digestion happens in the cecum and large colon, where billions of microorganisms break down fiber from grass and hay. Their stomachs are surprisingly small for such large animals - only about 2-4 gallons - which means they're designed to eat small amounts continuously throughout the day rather than big meals.
In the wild, horses graze for 14-18 hours a day, constantly moving and nibbling. Their digestive system produces stomach acid around the clock, whether they're eating or not. When a horse goes too long without food, that acid has nothing to buffer it, which is why long gaps between meals can cause ulcers. This is the single most important fact about horse nutrition: horses need near-constant access to forage.
Forage: The Foundation of Every Horse's Diet
Forage - meaning hay and/or pasture grass - should make up the vast majority of your horse's diet. We're talking 1.5% to 2.5% of body weight daily in forage for most horses. For a 1,000-pound horse, that's 15-25 pounds of hay per day.
Types of Hay
- Grass hay (timothy, orchard, bermuda) - The workhorse of horse diets (pun intended). Lower in calories and protein than legume hay, which makes it ideal for most horses, especially easy keepers. Timothy hay is the gold standard in many regions.
- Legume hay (alfalfa, clover) - Higher in protein, calcium, and calories. Excellent for growing horses, lactating mares, and hard-working performance horses. Too rich for many pleasure horses and easy keepers.
- Mixed hay - A blend of grass and legume, offering a middle ground. Many horse owners find a timothy-alfalfa mix works well.
What Makes Good Hay
Not all hay is created equal, and learning to evaluate hay quality is one of the most practical skills a horse owner can develop.
- Color - Should be green to greenish-yellow. Brown or bleached hay has lost much of its nutritional value.
- Smell - Fresh, slightly sweet hay smell. If it smells musty, dusty, or moldy, don't feed it. Mold can cause serious respiratory and digestive problems.
- Texture - Leafy and soft is better than stemmy and coarse. Leaves contain more nutrition than stems.
- Cleanliness - Check for weeds, debris, insects, and mold. Break open a few bales and inspect the interior.
- Maturity - Hay cut earlier in its growth cycle has more nutritional value. Overly mature hay is stemmy and less digestible.
When in doubt, get your hay tested. A forage analysis costs around $20-40 and tells you exactly what your hay provides nutritionally. This isn't overkill - it's good horse management.
Pasture
Good pasture is nature's perfect horse food. Horses that live on well-managed pasture often need little to no supplemental hay during growing season. But pasture management is a whole skill set:
- Rotate grazing areas to prevent overgrazing and parasite buildup
- Keep pastures mowed and fertilized appropriately
- Test soil and reseed as needed
- Control weeds, especially toxic plants (more on this below)
- Be aware of fructan levels in grass, which peak in cool temperatures and sunny conditions - this matters especially for horses prone to laminitis
Concentrates: Grain and Pelleted Feeds
Here's something that surprises a lot of new horse owners: many horses don't need grain at all. A horse in light work or no work that maintains good body condition on quality hay alone doesn't need concentrated feed added to the mix.
Grain and commercial feeds are calorie supplements. They're for horses whose energy needs exceed what forage alone can provide - hard-working performance horses, growing youngsters, pregnant and lactating mares, and hard keepers that struggle to maintain weight.
Types of Concentrates
- Whole or processed grains - Oats, barley, corn. Oats are the safest individual grain because they're lower in starch and less likely to cause digestive upset. Corn is the highest in calories but also highest in starch.
- Commercial pelleted feeds - Pre-mixed, balanced feeds designed for specific life stages and workloads. These are often the simplest option because the manufacturer has already balanced the nutrients.
- Beet pulp - A high-fiber, moderate-calorie feed that's excellent for adding weight without excess starch. Soak it before feeding (dried beet pulp expands significantly).
- Rice bran - Another calorie-dense option that's lower in starch than grain. Good for hard keepers.
Feeding Rules for Concentrates
- Never feed more than 5 pounds of grain in a single meal - Overloading the small stomach with starch can cause colic or laminitis.
- Split into multiple meals - If your horse needs grain, divide it into 2-3 meals throughout the day.
- Always feed hay before grain - Hay slows the passage of grain through the digestive system, improving nutrient absorption and reducing the risk of problems.
- Change feeds gradually - Any diet change should happen over 7-14 days, slowly mixing new feed with old. Abrupt changes disrupt the gut microbiome and can cause colic.
Water: The Most Overlooked Nutrient
Horses drink 5-10 gallons of water per day at rest, and that can double or triple with heavy exercise, hot weather, or lactation. Dehydration is serious in horses and can lead to impaction colic, which is one of the most common emergencies in equine medicine.
- Provide clean, fresh water at all times - no exceptions
- Clean water buckets and troughs regularly; algae and contamination reduce water intake
- In winter, horses drink less cold water. Heated water buckets or tank heaters encourage adequate intake.
- After hard exercise, allow horses to drink small amounts frequently rather than gulping large quantities at once
- A pinch test on the neck can check hydration - if the skin stays tented for more than 2 seconds, the horse may be dehydrated
Salt and Minerals
Every horse needs access to salt. Horses lose electrolytes through sweat, and unlike humans, they can self-regulate salt intake pretty well if given the opportunity.
- Provide a plain white salt block or loose salt in the stall or pasture at all times
- Mineralized salt blocks (the red or brown ones) provide trace minerals in addition to sodium chloride
- Horses in heavy work during summer may benefit from electrolyte supplementation in their water or feed
- Don't rely solely on a salt block - some horses don't lick enough. Adding 1-2 tablespoons of loose salt to daily feed ensures adequate intake.
Foods That Are Dangerous for Horses
Horses are surprisingly vulnerable to certain common plants and foods. This isn't an exhaustive list, but these are the ones every owner needs to know:
Toxic Plants
- Red maple leaves - Wilted or dried leaves cause destruction of red blood cells. Can be fatal. Keep horses away from red maple trees.
- Yew - All parts are extremely toxic. Even a small amount can cause sudden death.
- Black walnut - Shavings from black walnut used as bedding cause laminitis within hours. The trees themselves are also problematic.
- Ragwort - Causes irreversible liver damage. Horses usually avoid it fresh but may eat it dried in hay.
- Oleander - All parts extremely toxic. Common ornamental plant in warmer climates.
Foods to Avoid
- Lawn clippings - They ferment rapidly and can cause fatal colic. Never dump grass clippings in a horse pasture.
- Bread and bakery products - Can form a dough ball in the stomach and cause obstruction.
- Cruciferous vegetables - Broccoli, cabbage, and cauliflower cause excessive gas.
- Chocolate - Contains theobromine, which is toxic to horses.
- Avocado - All parts of the plant are toxic to horses.
Safe Treats
Horses love treats, and in moderation, these are fine: carrots, apples (cut into pieces to prevent choking), watermelon, bananas, peppermint candies, and sugar cubes. Keep treats small and infrequent - you don't want to create a nippy, pushy horse that mugs you for snacks.
Feeding Schedules and Practical Tips
Consistency is everything in horse feeding. Horses have internal clocks that would put most humans to shame, and they get anxious when meal times shift unpredictably.
- Feed at the same times daily - Most barns feed twice a day (morning and evening), with hay available between meals.
- Maximize forage access - Slow-feed hay nets extend eating time and reduce the gap between meals. This is especially important for stall-kept horses.
- Feed by weight, not volume - A coffee can of oats weighs differently than a coffee can of pellets. Use a kitchen scale or a hanging feed scale.
- Monitor body condition regularly - Use the Henneke Body Condition Scale (1-9). Aim for a 5-6 for most adult horses. Adjust feed up or down based on what you see and feel.
- Separate horses at feeding time - Dominant horses will bully others away from food, leading to uneven nutrition in group settings.
Nutrition doesn't have to be complicated. For most horses, good quality hay in adequate amounts, clean water, salt, and appropriate concentrates (if needed) will keep them healthy and thriving for years. When in doubt, consult an equine nutritionist or your vet. They can help you build a feeding plan based on your specific horse's age, workload, body condition, and health needs.