Alfalfa for Horses
Alfalfa was recently a topic of discussion on The Naturally Healthy Horse‘s Facebook page, and it seems that there are a few myths surrounding this type of forage. I, personally, do not feed alfalfa hay, but I do feed my horses a handful of soaked alfalfa pellets (mixed with soaked timothy hay pellets) as a carrier for my minerals.
Many horses do just fine eating alfalfa, while others show sensitivity to it. One thing is clear though: alfalfa should not be a horse’s sole source of nutrients.
Let’s start with a few facts about alfalfa. Alfalfa is:
- High in protein;
- Calorie dense (20-25% more calories than grass hays);
- High in calcium;
- Low in sugar; and
- Readily accepted by most horses.
Depending on your horse’s needs, these facts could be a good or bad thing. For example, the higher protein content of alfalfa is a good thing for a growing horse or a pregnant/ lactating mare. But if your horse doesn’t need the extra protein, it comes out in the urine as urea–and this can actually be detrimental to the environment as shown in this article I wrote for The Horse.
The fact that alfalfa is calorie dense could be a good thing again for a horse that needs to gain weight or for a growing horse, but obviously it wouldn’t be so great for an overweight horse.
While some people may consider the fact that alfalfa is high in calcium to be a good thing, again, it depends! True, horses need calcium in their diet, but they also need phosphorus and magnesium– and in the correct ratios. The optimal calcium: phosphorus ratio lies between 1.2-2: 1 while the optimal calcium: magnesium ratio is between 1.5-2: 1. These ratios can be distorted quite easily when you throw a few flakes of alfalfa in the mix. If you feed much alfalfa at all, you need to feed something else rich in phosphorus (like rice or wheat bran) and something high in magnesium (see this post for sources of magnesium) to go with it. You can even buy ration balancers such as this one for alfalfa-based diets.
Cautions with Alfalfa
I don’t want you to be afraid to feed alfalfa, but there are a few things you need to watch out for if you do feed it:
- Mold: Alfalfa is more prone to molding than grass hays. Bales should always be checked carefully before being fed;
- Blister Beetles: These insects like to eat alfalfa too and may be harvested with the hay. The beetles contain cantharidin,a toxic defensive chemical that protects them from predators. Even just a tiny part of a blister beetle can be deadly if ingested by a horse. Blister Beetles are more of a problem in eastern and central U.S.
- Laminitis Sensitivity: Some insulin resistant horses seem to be sensitive to alfalfa. And regarding this sensitivity, Dr. Eleanor Kellon, VMD, says this: “The cause isn’t entirely clear, but it may be related to alfalfa having more sugar in the form of glucose, and higher starch.”
- Enteroliths: High alfalfa diets have been linked with enteroliths (“stones”) in the digestive system, which can cause impaction colic, which will likely need surgery to resolve. According to a report from the College of Veterinary Medicine at the University of California at Davis, 98% of the horses treated by U.C., Davis veterinarians were fed a diet that contained at least 50% alfalfa hay.
If you do feed alfalfa, a good rule of thumb is that it make up no more than 10-20% of your horse’s total diet. So while no horse’s diet should be made up primarily of alfalfa, it definitely has its benefits and it’s place in some equine diets.