As with a number of things in the horse world, many people have strong opinions about alfalfa hay. Those opinions range from “it’s the best thing ever” to “there is no way I am ever feeding that to my horse”.

The nutritional profile of alfalfa is neither good nor bad; however, we need to be aware of the unique attributes of alfalfa to ensure that it is incorporated into the diet in a way that is beneficial to the horse.

On average, alfalfa is higher in protein compared to grass varieties of hay. A diet that incorporates a high proportion of alfalfa as the source of forage will supply crude protein in excess of the horse’s daily requirements. Excess protein in and of itself is not an issue for healthy horses. They will break down the excess dietary protein into ammonia, which will be excreted in urine. They will create more urine in this process so you will find that your horse will consume more water and their stall will be more wet on this type of diet. This increases the amount of bedding used and if stalls aren’t managed appropriately, the buildup of ammonia can contribute to respiratory issues.

High dietary protein does not lead to kidney dysfunction in horses; however, pre-existing kidney issues are exacerbated by excess protein intake. Because the majority of the horse’s diet is forage, an alfalfa hay wouldn’t be recommended for a horse with kidney disease; however, alfalfa meal as a small component of a horse feed wouldn’t necessarily be a problem, provided the total protein content of the feed isn’t excessive.

The mineral profile of alfalfa differs from grass hays. On average, alfalfa is much higher in calcium. When balancing diets, the calcium to phosphorus ratio is something we look very closely at for certain classes of horses. The mature adult horse who is not used for breeding can tolerate a wide calcium to phosphorus balance (7:1) as long as the minimum phosphorus requirement is met. For these horses, we don’t necessarily need to feed a product specifically designed to complement a high alfalfa forage.

On the other hand, the diets of broodmares and growing horses needs to be very carefully balanced for a calcium to phosphorus ratio between 1:1 and 2:1. The risk of developmental orthopedic disorders increases significantly when the calcium to phosphorus ratio exceeds 2:1, which is often the case of grass/alfalfa blends and almost always the case in a straight alfalfa hay diet. Maintaining the proper balance throughout gestation, lactation and through the growth of the young horse is key to supporting proper growth. Most feeds are not designed to supply enough phosphorus to offset a high calcium forage. Tribute® Superior Equine Nutrition has designed Alfa Essentials® and Alfa Growth® to supply a greater amount of phosphorus (as compared to calcium) in order to complement a high alfalfa diet.

As a general rule of thumb, Alfa Essentials® and Alfa Growth® are designed to complement a diet that is 50% or greater alfalfa. We recommend using a hay analysis to confirm that exact calcium to phosphorus ratio of the diet used in breeding operations, as visual inspection of hay cannot guarantee the correct ratio will be achieved.

One of the perceived issues commonly cited by the “there is no way I am ever feeding that to my horse” camp is that alfalfa makes horses hot. It was long thought that the protein content of feed drove hyperactivity in horses; however, we now know that sugars and starches drive hyperactive behavior. Read more on this in our Feeding the Hyperactive Horse article. Alfalfa, on average, is lower in sugars and starches than grass hays, but it is also more energy dense and the flakes are often heavier. Therefore, switching from 2 flakes of grass hay to 2 flakes of alfalfa would provide more total pounds of forage and that forage would provide more energy (calories) per pound. More forage and more calories simply give the horse more available energy. This can be very helpful when you are working to put weight on a horse, but a horse that is already in good weight may use the additional energy for purposes that aren’t as desirable.

Alfalfa as a component of the diet brings in high quality protein and highly digestible fiber that is translated to a good calorie source for weight gain or to support work. Alfalfa meal brings these attributes to horse feeds and an alfalfa/grass blend hay, or adding a few flakes of alfalfa to a grass-based diet, can be beneficial. A 100% diet of alfalfa forage isn’t detrimental when additional steps are taken to ensure the total diet is balanced and the stable can be managed in a way that doesn’t result in ammonia buildup.

For questions about your horse’s diet, please contact us!

Nicole Rambo, Ph.D.