It is fine to feed grass hay or alfalfa hay to healthy horses! In some parts of the country grass hay is hard to grow so they primarily feed alfalfa to their horses. Interestingly, in the Midwest many horse owners got the impression that alfalfa is bad to feed to horses. Alfalfa is higher in protein, potassium and calcium than grass hay and most alfalfa in Wisconsin is grown for dairy cattle so it is often too stemmy for horses. But if you had a nice soft alfalfa can be safely fed it to your healthy horse. Alfalfa’s higher protein content should help your horse build and maintain muscle and any extra protein is readily excreted in the urine. Alfalfa should not make horses “hot” or crazy. Sugar containing foods such as grains, sweet feed, and green grass may cause horses to have excess pent up energy and should not be fed in excess.
Because alfalfa is higher in potassium, if you have a horse with HYPP alfalfa should NOT be fed.