Last updated: September 18, 2026
You’ve probably heard two very different opinions about alfalfa hay. Some people say it’s one of the best feeds you can give a horse; others warn that it makes horses too hot, too fat, or creates health problems. So which is it?
Alfalfa isn’t automatically good or bad—it depends on the horse and the rest of the ration. It’s a nutrient-dense forage that can be an excellent choice for hard-working horses, hard keepers, growing horses, and horses that need more calories or quality protein. But for easy keepers or horses with metabolic concerns, it may provide more nutrition than they need unless the hay and overall diet are evaluated carefully.
I’ve spent more than 30 years hauling, stacking, and feeding hay in Louisiana barns, from Thoroughbreds in training to easy-going horses that can gain weight looking at a feed bucket. In this guide, I’ll walk through how much alfalfa to feed, which horses benefit most, when to be cautious, how to evaluate a good bale, and what I look for before bringing a new load into the barn.
Table of Contents
How Much Alfalfa Should You Feed?
Start with total forage, not the alfalfa amount by itself. Most horses need about 1.5% to 2% of body weight in total forage per day – for a 1,000-pound horse, that’s roughly 15 to 20 pounds of hay. I rarely feed 100% alfalfa. I treat it as a strategic part of that total ration, not a replacement for it.
Example: Starting an Alfalfa Ration for a 1,000-Pound Horse
Calculate the horse’s total daily forage first. At 1.5% to 2% of body weight, a 1,000-pound horse commonly needs about 15 to 20 pounds of forage dry matter a day. If that horse is in regular work, needs help holding condition, and the hay analysis supports it, I might start with 5 pounds of alfalfa and the balance as grass hay. Then I’d reassess body condition, manure, appetite, and workload before increasing it.
That’s a starting point, not a prescription. Bale moisture, pasture access, concentrate feed, age, teeth, medical history, and the specific hay analysis can all change the right answer for your horse.
Here’s how I think about the alfalfa portion by horse type. Weigh hay whenever you can – flake size and bale weight vary too much to use flakes as a reliable measure.
| Horse Type | Alfalfa Portion of Forage | What This Means |
|---|---|---|
| Race or hard training | Often a significant share of total forage | Balance with grain and workload; back off if you smell strong ammonia in the stall |
| Hard keepers | Meaningful portion, introduced gradually | Introduce over 10-14 days and monitor weight weekly until you hit the target |
| Pregnant or lactating mares | Meaningful portion, especially late gestation | Alfalfa alone still won’t cover all energy needs – keep concentrate support in place |
| Growing horses (weanling-2yo) | A blended portion, not straight alfalfa | Always pair with a phosphorus source to balance the ration |
| Seniors with poor teeth | Can make up most of the forage ration | Soak pellets into a mash if chewing is significantly compromised |
| Maintenance adults | Small amount or none | A little improves palatability without overshooting the calorie or protein budget |
| Easy keepers | Little to none | Most do fine on tested, clean grass hay with a slow-feeder to stretch eating time |
| Metabolic or laminitis-history horses | Individualized | Use a tested hay analysis and a vet or qualified nutritionist’s plan, not a general percentage |
Never switch a horse’s hay cold turkey. I use a 10 to 14 day transition: roughly a quarter alfalfa for the first few days, half by the end of the first week, three-quarters by the second week, then the target ratio if the horse is tolerating it well – normal manure, no loose stools or signs of discomfort. Watch your stall, too: horses on more alfalfa urinate more and stalls can smell sharply of ammonia. That’s the kidneys excreting excess nitrogen from protein metabolism, and it’s normal, but good ventilation matters more once you’re feeding heavier.
When Alfalfa Helps
I had one Thoroughbred colt that looked like he was burning fuel faster than I could put it in him – stiff and flat the morning after hard work, no matter what I fed. Moving him to a diet with more alfalfa alongside his grain ration made a real difference within a few weeks: noticeably less morning stiffness and better recovery. Alfalfa is a legume, not a grass, which is why it runs higher in protein, calcium, and energy than timothy or bermuda – useful when a horse’s workload or condition calls for more of all three.
Hard keepers and underweight horses respond well to the higher calorie density – more energy per pound of hay consumed – and I’ve found palatability is consistently excellent, even with horses that pick at stemmy grass hay. Seniors with worn or missing teeth often do better on it too, since the softer, leafier texture is easier to chew and process than coarse, mature grass hay.
Growing horses, and mares in late gestation or lactation, also have elevated protein and calcium needs that alfalfa helps meet – but growth and broodmare diets should be balanced by a vet or nutritionist for the full ration, not built around alfalfa percentages alone. I’ll cover the calcium-to-phosphorus side of that in the next section.
Alfalfa’s calcium and protein content may also help buffer stomach acid, and some studies have shown reduced ulcer severity scores in horses fed alfalfa versus grass hay alone. I feed a bit of alfalfa in the evening for track horses that go without grazing overnight, as one piece of a broader ulcer management approach – not a substitute for it. If your horse has confirmed gastric disease, work that into the plan with your vet rather than relying on alfalfa alone.
When to Limit Alfalfa or Get Professional Help
Alfalfa isn’t automatically the right call, and I’ve learned some of this the expensive way. A few situations are worth real caution.
Easy keepers and obesity-prone horses. This is the most common mistake I see. A stocky Quarter Horse or pony that holds weight on air doesn’t need hay that’s meaningfully more energy-dense than what it’s already eating. Extra calories add joint stress and laminitis risk. For easy keepers, stick to mature, clean, tested grass hay with a suitable calorie and sugar profile, limit portions, and use a slow-feeder net to stretch eating time.
Metabolic horses (EMS, PPID, insulin resistance, laminitis history). Alfalfa’s average sugar and starch content tends to run lower than grass hay, but “on average” isn’t good enough here – individual batches vary, and some test well above what’s safe for a metabolic horse. Get a tested hay analysis and work with your vet or an equine nutritionist rather than feeding by general guidelines.
Growing horses. A calcium-heavy, all-alfalfa diet can push the calcium-to-phosphorus ratio well outside the ideal range for developing horses, which makes the overall ration harder to balance and, combined with excess energy, is one contributing factor in developmental orthopedic problems. I always blend alfalfa with grass hay for growing horses and pair it with a concentrate that supplies extra phosphorus.
Enterolith risk in some regions. In parts of California and the Southwest with alkaline water, high-alfalfa diets have been identified as a risk factor for enteroliths – mineral stones that can form in the gut and cause severe colic, particularly in Arabians, Morgans, and miniature horses. If you’re in one of those regions, keeping alfalfa to roughly half or less of total forage is the standard recommendation.
Kidney disease. Horses with compromised kidneys struggle to handle the higher protein load in a high-alfalfa diet. This is uncommon, but if your vet has flagged kidney concerns, that’s a ration change to make under their direction, not on general advice.
Blister beetles are worth taking seriously. Blister beetles can end up baled into alfalfa, particularly in the southern and central U.S. The toxin they carry, cantharidin, has no known antidote, and even a small amount can be fatal to a horse. Only buy from growers who actively manage their fields for beetle activity, and ask them directly about their scouting practices before you buy.
Dusty or moldy hay. A batch that looked fine from the outside once cost me a $400 vet visit after it turned out dusty and borderline moldy in the middle bales. Alfalfa’s dense, leafy structure traps moisture differently than grass hay, so pull a flake from the center of several bales and smell it before you buy – musty, sour, or hot to the touch means walk away.
Choosing and Testing Alfalfa Hay
You can’t judge hay by color alone – that $400 batch looked green and premium from the outside. Here’s what I actually check before I buy.
Pull a flake from the middle of several bales, not just the ones on the outside of the stack, and check for:
- Color: green to greenish-gold – yellowed, sun-bleached, or brown means nutrient loss and over-maturity
- Smell: clean and faintly sweet – musty, sour, or ammonia-like means mold or heat damage
- Texture: leafy with good leaf retention – heavy stems and few leaves means it was cut too late
- Dust: minimal – a dust cloud when you pull a flake is a respiratory hazard, full stop
- Temperature: the middle of the bale shouldn’t feel warm – heat means active fermentation and a mold or fire risk
For any horse with metabolic concerns, a lab test isn’t optional – averages don’t tell you what’s actually in your specific batch. For bulk purchases from a new source, a hay test typically runs $25 to $40, which is cheap insurance against a bad load. Most county extension offices lend out hay probes for free; LSU AgCenter’s forage lab is one option if you’re in Louisiana. You’re generally looking for crude protein in the 15% to 22% range, sugar and starch under 12% (under 10% for a metabolic horse), and no strong mold or heat signs. I test every new source, and at least annually even from an established one.
Please note: Everything here reflects general guidelines from 30+ years of barn experience, not veterinary or professional nutritionist advice. Feeding decisions for metabolic horses (PPID, EMS, insulin resistance, or a laminitis history) should be made with a licensed equine veterinarian or certified equine nutritionist, based on a tested hay analysis rather than general ranges like these.
Alfalfa also carries a real price premium over grass hay, and that gap tends to run wider here in Louisiana than in the Midwest, since almost all of what I buy ships in from out of state. If you’re weighing whether the premium is worth it for your barn, the numbers and per-ton math are worth working through separately – see my hay cost guide for current regional pricing and the cost-per-ton formula, and timothy vs. bermuda vs. alfalfa if you’re still deciding between hay types. If a slow-feed net or different form (pellets or cubes) would help you control waste or cost, see alfalfa pellets vs. cubes.
FAQs About Alfalfa Hay for Horses
How much alfalfa should I feed a 1,000-pound horse?
Start with total forage at 1.5% to 2% of body weight per day – about 15 to 20 pounds for a 1,000-pound horse. For a hard-working horse or hard keeper, a common starting point is 5 to 10 pounds of alfalfa within that total, with the rest as grass hay. Maintenance horses usually need little or none. Adjust based on body condition, workload, and a hay analysis.
Can horses eat alfalfa hay every day?
Yes, many horses eat some alfalfa daily as part of a mixed forage ration. Feeding alfalfa as the sole forage is less common and needs more care, since it can create protein and calcium levels well beyond what most horses need. Most experienced owners blend it with grass hay rather than feeding it exclusively.
Is alfalfa safe for horses with PPID, insulin resistance, or a laminitis history?
It depends on the individual batch and the horse’s overall management plan. Alfalfa’s average sugar and starch content tends to run lower than grass hay, but individual samples vary. Get a tested hay analysis and work with your veterinarian or a certified equine nutritionist before feeding alfalfa to a metabolic or laminitis-history horse – do not rely on general guidelines alone.
Does alfalfa make horses hot?
Not directly. Sugars and starches are more closely tied to excitable behavior than protein is. What often happens is that switching to alfalfa increases total calorie intake without an equivalent reduction elsewhere, and the horse ends up with more energy than its workload uses. Adjusting the amount, rather than avoiding alfalfa altogether, usually resolves it.
Can alfalfa help horses with ulcers?
It may help as one part of a broader management plan. Alfalfa’s calcium and protein content can help buffer stomach acid, and some research has shown reduced ulcer severity scores in horses fed alfalfa compared to grass hay alone. It’s a useful management tool, not a treatment – work with your vet for a horse with confirmed gastric disease.
How do I choose good-quality alfalfa hay?
Look for green to greenish-gold color, a clean and faintly sweet smell, good leaf retention with minimal stem, little to no dust, and no warmth in the middle of the bale. Pull flakes from several bales in the stack, not just the outside ones. For any horse with metabolic concerns, get a lab test rather than relying on a visual check alone.
Alfalfa isn’t automatically better than grass hay – it’s simply more concentrated. Match it to a horse that can actually use that extra protein, calcium, and energy, weigh what you’re feeding instead of guessing by the flake, and test any hay you’re not already sure of. That’s the whole decision, worked out the slow way over 30 years so you don’t have to.
About Miles Henry
Racehorse Owner & Author | 30+ Years in Thoroughbred Racing
Miles Henry (legal name: William Bradley) is a professional horseman based in Folsom, Louisiana. He holds Louisiana Racing License #67012 and has spent over three decades managing Thoroughbreds at premier tracks including Fair Grounds, Delta Downs, and Evangeline Downs.
Expertise & Hands-On Experience: Beyond the track, Miles has decades of experience in specialized equine care, covering everything from hoof health and nutrition to training protocols for Quarter Horses, Friesians, and Paints. Every guide on Horse Racing Sense is rooted in this “boots-on-the-ground” perspective.
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