The question of whether alfalfa and hay are the same is a common source of confusion. While the two terms are related, they are not interchangeable, representing a difference in both botanical classification and nutritional profile. Understanding this distinction is fundamental because it affects feeding strategies for various livestock and domestic animals.
Understanding What Hay Is
Hay is a generic term for grasses, legumes, or other herbaceous plants that have been cut, dried, and cured for animal fodder. The key characteristic is drying the forage to a low moisture level to prevent spoilage, allowing it to be preserved and fed when fresh pasture is unavailable. Therefore, “hay” defines a processed product rather than a specific plant species. Grass hays, which come from the grass family (Poaceae), are the most common type, including varieties like Timothy, Orchard Grass, Fescue, and Bermuda grass.
Alfalfa: The Legume Difference
Alfalfa, scientifically known as Medicago sativa, is a perennial flowering plant belonging to the pea family, making it a legume, not a grass. This botanical classification is the core distinction from common grass hays. Alfalfa is often referred to as legume hay, and it is valued for its ability to fix nitrogen in the soil. Its nutritional value is concentrated in its leaves, which, when properly cured, provide high-quality forage.
Key Nutritional and Compositional Differences
The most significant difference between alfalfa and grass hay lies in their nutrient composition, which stems directly from their botanical nature. Alfalfa hay provides a much higher concentration of protein, typically ranging from 16 to over 21 percent on a dry matter basis. In contrast, common grass hays generally contain crude protein levels between 8 and 10 percent. Alfalfa is also a major source of dietary calcium, often containing two to three times the amount found in grass hays.
The energy density is also higher in alfalfa, providing more digestible energy per pound than most grass hays. Alfalfa hay tends to have a lower concentration of non-structural carbohydrates, which include sugars and starches, compared to many grass hay varieties.
While grass hay has a higher overall fiber content, this fiber is often less digestible. This provides greater effective fiber for gut function and promotes a feeling of fullness in animals.
Practical Applications and Feeding Recommendations
Because of its nutrient density, alfalfa is typically reserved for animals with elevated energy and protein requirements. This includes animals in their high-growth stages, those in late gestation, or females that are lactating and producing milk. Dairy cattle and young, growing animals often benefit from the high protein and calcium provided by alfalfa. It is also a suitable choice for animals needing to gain weight or those recovering from illness, as a smaller volume provides more concentrated nutrition.
Grass hay, with its lower caloric and protein content, is generally the preferred forage for adult animals at maintenance or those needing weight management. Its bulk and lower energy density allow animals to consume the necessary volume of forage for digestive health without taking in excess calories.
In many cases, a blend of alfalfa and grass hay is used to tailor the diet precisely. This balances the high nutritional benefits of alfalfa with the gut-filling fiber of grass hay, allowing caretakers to manage nutritional demands while promoting continuous foraging behavior.