Alfalfa (Medicago sativa) is a legume forage crop and one of the most nutrient-dense feeds available to horses. Compared to grass hays such as timothy or orchard grass, alfalfa carries significantly more crude protein (typically 15–20% vs. 8–12%), higher calcium, and greater digestible energy per pound. This density makes it effective for horses with elevated nutritional demands — growing foals, mares in late pregnancy or lactation, performance horses in heavy work, and underweight horses needing condition gain.
The same density is a liability for horses that don’t need it. An easy-keeper gelding on alfalfa is likely to gain excess weight, and the high calcium-to-phosphorus ratio in a strictly alfalfa diet can contribute to developmental orthopedic disease in rapidly growing youngsters when not balanced with phosphorus sources. Horses prone to hyperkalemic periodic paralysis (HYPP) should avoid alfalfa because of its high potassium content.
In practice, many owners feed a mix of grass hay and alfalfa, adjusting the ratio to the horse’s workload and body condition. Alfalfa is also available as cubes or pellets, which are convenient for soaking as a mash for horses with dental problems. For a complete look at matching forage to budget and horse type, see feeding on a budget and the body condition scoring guide.
Further Reading
- Alfalfa (Medicago sativa) — Wikipedia entry covering botany, cultivation, and nutritional profile of this legume forage.
- Forage quality and equine digestive health — research on legume hay composition and its effects on horse gut physiology (PubMed Central).