What Is Alfalfa Hay? Feeding Guidelines for Horses

Alfalfa hay is the most argued-over forage in the UK and South African horse world. Fans call it the perfect ulcer-buffering protein boost. Critics blame it for fizzy behaviour, laminitis and kidney strain. The truth sits between the two: alfalfa hay is a powerful tool when it suits the horse, and a poor choice when it does not.

This guide explains what alfalfa hay actually is, how its nutritional profile compares with meadow and timothy hay, which UK and SA horses benefit from it, which should avoid it, how to feed it safely, and how it stacks up against the bagged chaff and pellet alternatives from Dengie, HorseHage and Spillers.

What Is Alfalfa Hay

Alfalfa (Medicago sativa), also known as lucerne in much of the Commonwealth including South Africa, is a perennial legume in the same family as peas and clover. It is not a grass. Its deep tap root (up to 6 metres in mature stands) fixes nitrogen and accesses minerals far below the reach of shallow-rooted grasses, which is why alfalfa is nutrient-dense and drought-tolerant.

Cut at the early flowering stage and dried, alfalfa becomes alfalfa hay: a green leafy forage with stems coarser than meadow hay and a higher leaf-to-stem ratio. In the UK it is most commonly imported from European or Canadian producers in compressed mini-bales, or sold chopped and dust-extracted as branded chaff by Dengie, HorseHage and Spillers. In South Africa, lucerne hay is widely grown in the Karoo, Eastern Cape and Northern Cape and forms the backbone of many sport-horse diets.

Alfalfa Hay Nutritional Profile

Typical nutritional values per kilogram of dry matter for good-quality alfalfa hay:

• Digestible energy: 9 to 11 MJ/kg DM (around 30 per cent more than average meadow hay).
• Crude protein: 16 to 22 per cent (against 7 to 11 per cent in meadow hay).
• Lysine: 0.8 to 1.2 per cent (the limiting amino acid for muscle development; meadow hay is usually deficient).
• Calcium: 1.2 to 1.8 per cent (around five times higher than meadow hay).
• Phosphorus: 0.2 to 0.3 per cent.
• Calcium-to-phosphorus ratio: typically 5:1 to 8:1.
• Magnesium: 0.25 to 0.35 per cent.
• Water-soluble carbohydrates (WSC): 6 to 10 per cent (lower than many UK ryegrass-heavy meadow hays).
• Starch: 1 to 2 per cent.
• Acid Detergent Fibre (ADF): 30 to 38 per cent.

The low WSC and starch numbers are why alfalfa is sometimes recommended for laminitis-prone horses, though the higher calorie density complicates that picture. The high calcium content is a powerful gastric buffer but skews the overall mineral balance and must be corrected if alfalfa is fed in large quantities.

Alfalfa Hay vs Meadow and Timothy Hay

Each forage has a place in a UK or SA feeding plan.

• Meadow hay. Mixed UK grass species. Moderate energy and protein. WSC can swing high in ryegrass-dominant fields. Most economical bulk forage.
• Timothy hay. Single-species grass. Lower energy, lower protein, lower calcium. The gold-standard hay for laminitics, easy keepers and horses prone to fizzy behaviour. More expensive in the UK; less common in SA.
• Alfalfa hay (lucerne). Legume forage. High energy, high protein, very high calcium. Best suited to growing, lactating, working or hard-keeping horses.
• Oat hay or barley straw. Low-protein low-energy bulk options for restricted-calorie diets.

For most adult leisure horses in light work, a 70 to 90 per cent meadow or timothy hay base with 10 to 30 per cent alfalfa hits the balance: enough alfalfa to buffer gastric acid and supplement protein, not so much that calcium and calories run away.

Benefits of Alfalfa Hay for Horses

Alfalfa hay delivers four clear benefits when matched to the right horse.

Protein and Amino Acid Quality

Alfalfa provides nearly twice the crude protein of meadow hay and, crucially, the right amino acid profile. Lysine, the first limiting amino acid for muscle building and topline development, is around three times more abundant in alfalfa than in grass hays. Horses building muscle (young stock, returning racehorses, eventers in fast work) often respond visibly to alfalfa supplementation within 6 to 8 weeks.

Gastric Acid Buffering

The high calcium and protein content of alfalfa neutralises stomach acid. The dense fibrous mat created by chewing long-stem alfalfa physically prevents acid splashing onto the squamous mucosa during exercise. A 2007 University of Tennessee study published in the Journal of Animal Science found horses fed alfalfa-based diets had significantly lower ulcer severity than horses on grass hay alone. The protective effect is now standard veterinary advice for any horse in regular work.

Palatability and Condition

Most horses prefer alfalfa to grass hay once they have tried it. For hard-keepers, post-operative or convalescing horses, and senior horses with poor dentition who struggle on stemmy hay, soaked alfalfa cubes or chaff often turn around appetite and condition within two to four weeks.

Low Sugar and Starch Profile

Alfalfa is naturally low in sugar and starch. For metabolic horses where weight is not the primary concern, alfalfa can be a useful component of a low non-structural carbohydrate (NSC) diet, though portion control matters.

Which Horses Benefit From Alfalfa

• Young, growing horses needing lysine for muscle and skeletal development.
• Lactating mares supporting a foal at foot.
• Performance horses in moderate to hard work (eventing, racing, polo, endurance).
• Hard-keeping seniors struggling to maintain weight on grass hay.
• Horses with confirmed or suspected gastric ulcers (alongside veterinary treatment).
• Horses with poor dentition; chopped alfalfa or soaked pellets are easy to chew.
• Horses needing to gain topline after illness or post-rehabilitation.

Which Horses Should Avoid Alfalfa

Alfalfa is not for every horse. The same nutrient density that helps a hard-keeping eventer can ruin a native pony.

• Native breeds and easy keepers. Welsh ponies, Shetlands, Highlands, Connemaras, Exmoors, Dartmoors. High-calorie alfalfa drives weight gain, laminitis risk and the cresty neck of insulin dysregulation.
• Horses with kidney disease. The high protein and calcium load worsens nitrogen and mineral excretion. Always consult a vet first.
• Horses with enterolith (gut stone) history. The high calcium content predisposes to gut stones, especially in Arabians and Arab-crosses housed indoors on alfalfa-heavy diets.
• Horses prone to filled legs or stocking up. Some horses develop puffy legs on alfalfa-heavy diets, likely related to protein metabolism and ammonia load.
• Horses fed pre-mixed cubes already heavy on alfalfa. Stacking alfalfa hay on top of an alfalfa-based hard feed pushes total protein above 18 per cent of the diet, which is usually unnecessary.
• Excitable types prone to fizzy behaviour. Some horses are sensitive to the protein and energy load. Lower-energy alternatives exist.

Alfalfa and Gastric Ulcers

The 2015 ECEIM consensus statement on equine gastric ulcer syndrome lists alfalfa as a recognised dietary intervention for both prevention and adjunctive treatment. The recommended protocol is straightforward.

• Feed a handful (around 150 to 250 g) of chopped alfalfa or three to five alfalfa cubes 20 to 30 minutes before exercise.
• The fibrous mat formed in the stomach floats on the acid layer and prevents splash damage to the squamous mucosa during fast work.
• The calcium and protein content buffers the acid that does reach the upper stomach.
• Continue alongside any omeprazole or sucralfate course prescribed by the vet.

This is not a replacement for veterinary diagnosis and treatment of ulcers in horses, but it is one of the most evidence-backed management tweaks an owner can make.

How Much Alfalfa Hay to Feed

For most adult leisure horses (450 to 550 kg) in light to moderate work, the working rule is 1 to 2 kg of alfalfa hay or chaff per day, fed alongside 6 to 10 kg of meadow or timothy hay.

• Leisure horse in light work, 500 kg: 0.5 to 1.5 kg alfalfa daily, with the rest of forage as meadow hay.
• Sport horse in moderate work, 500 to 600 kg: 1.5 to 3 kg alfalfa daily, split across feeds.
• Racing thoroughbred in fast work, 500 kg: 3 to 5 kg alfalfa daily under a vet or nutritionist’s guidance.
• Senior or hard-keeper, 450 to 500 kg: 2 to 4 kg alfalfa daily, ideally soaked alfalfa cubes for older teeth.
• Native pony or easy keeper: 0 to 0.5 kg alfalfa daily, or none at all.

Introduce alfalfa gradually over 7 to 14 days. Sudden large additions can cause loose droppings, gas colic and behavioural change. If the diet is more than 30 per cent alfalfa, ask a registered nutritionist or vet to balance for calcium-to-phosphorus ratio; you may need to add a phosphorus source such as wheat bran or a balancer specifically formulated for alfalfa-heavy diets.

Alfalfa Formats UK Buying Guide

UK and SA owners can choose between five practical formats.

• Long-stem alfalfa hay (small bale, mini-bale or large square). The most natural form. Best for top-stem chewing and saliva production. Sourced through livery yards and feed merchants; less commonly stocked in chain stores. UK price around £8 to £14 per small bale.
• Chopped alfalfa chaff (Dengie Alfa-A Original, Dengie Alfa-A Lite, HorseHage Alfalfa). Dust-extracted, molasses-free options widely stocked in UK feed stores. Easy to weigh and feed, ideal for the pre-exercise gastric buffer. UK price around £14 to £20 per 20 kg bag.
• Alfalfa cubes or pellets. Compressed for easy soaking and chewing by older horses. Higher density makes them useful for hard-keepers needing concentrated calories. UK price around £18 to £25 per 25 kg bag.
• Alfalfa-based haylage (HorseHage Alfalfa). Dust-free, sealed bales for stabled or respiratory-sensitive horses. UK price around £12 to £18 per bale.
• Bagged lucerne (South Africa). Available compressed in 25 to 30 kg bales. Karoo lucerne is the benchmark for sport-horse yards. Local pricing typically R80 to R140 per bale in 2026.

Dust-extracted formats are preferable for horses with any respiratory sensitivity. For horses with equine asthma or recurrent airway obstruction, switch all forage including alfalfa to haylage or steamed options.

Frequently Asked Questions

Is alfalfa hay okay for horses?

Yes, for most horses, in the right quantity. Performance horses, growing youngstock, lactating mares, hard-keepers and ulcer-prone horses benefit. Native ponies, easy keepers, kidney patients and enterolith-prone horses should have little or none.

What are the side effects of alfalfa in horses?

Loose droppings (especially during introduction), filled legs, behavioural fizziness in sensitive horses, urine smelling strongly of ammonia (from excess protein), and excessive calcium intake disrupting mineral balance. All are manageable through portion control and gradual introduction.

Is alfalfa the same as lucerne?

Yes. Alfalfa is the American name; lucerne is the British and South African name. Same plant (Medicago sativa), same nutritional profile.

Is alfalfa good for horses with laminitis?

Alfalfa is low in sugar and starch but high in calories. For overweight laminitics, the calorie load is the bigger problem. For lean laminitics (rare but possible) or PPID horses, small quantities of alfalfa can be useful under veterinary guidance. Discuss with a vet familiar with laminitis in horses before introducing alfalfa.

Can horses eat alfalfa hay all day?

Ad-lib alfalfa is rarely recommended for adult leisure horses. The calorie and calcium load is too high. Ad-lib mixed forage (meadow or timothy hay with a portion of alfalfa) is the sustainable approach. Lactating mares and growing foals can manage higher proportions under nutritional supervision.

How much alfalfa should I feed before exercise?

Around 150 to 250 g of chopped alfalfa, or three to five alfalfa cubes, 20 to 30 minutes before exercise. Enough to form a fibrous mat in the stomach without overloading the gut before work.

Is chaff the same as alfalfa?

Chaff is any chopped forage; alfalfa chaff is one type. UK feed stores sell straw chaff, oat chaff, meadow grass chaff and alfalfa chaff. Read the label: “chaff” alone means little.

For more on forage and feeding, see our guides to horse feeding 101 and how to make hay. For related health information see ulcers in horses explained.