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Alfalfa Hay for Horses The Good, the Bad, and the Not So Good

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Most horse owners I know feed their horses alfalfa daily. In contrast, I believe feeding alfalfa isn’t healthy unless a horse needs extra calories. Should you feed your horse alfalfa? The answer to this question is not a cut-and-dry one. It depends on what else you’re doing, their current level of exercise, their overall health, and what other types of food they eat.

Feeding alfalfa hay is good for horses with difficulty putting and keeping on weight and for those in training. Alfalfa is bad for fast-growing young horses and ones with liver or kidney problems. And alfalfa is not so good for horses that don’t need the extra calories or protein.

It’s hard to find reliable information about alfalfa online. That’s why I wrote this article to give you the information you need if you’re wondering whether you should feed alfalfa to your horses. You’ll find everything from feeding alfalfa, which horses need it, how much should be fed per day, whether it causes ulcers or colic in horses and more.

This article is one of a series of articles on horse hay I wrote, the main article being: Horse Hay: An Owner’s Guide.

Why is alfalfa good for horses?

Everyone wants to feed their horses correctly so they stay healthy, fit, and happy, and alfalfa could play a crucial role in achieving this goal. Alfalfa is an excellent source of protein, vitamins, and minerals essential for good health, such as calcium, magnesium, potassium, phosphorus, and iron.

It’s an excellent source of high-quality fiber that produces slow-release energy, which helps maintain weight and promote healthy digestion. But it can be expensive to feed your horse this high-quality hay, and although alfalfa has many benefits, it can also cause problems if not fed correctly or in the right amount.

Picture of a horse eating alfalfa hay.

Horses that benefit from eating alfalfa.

Alfalfa is a nutrient-dense forage containing crude proteins, calcium, and high-quality fiber without much sugar. These qualities make it excellent hay to feed underweight horses.

Also, horses that are insulin resistant can’t eat many grass hays because of their high sugar content, so alfalfa is a good alternative for them. Horses that work hard benefit from eating alfalfa because it’s a good protein source and replaces lost calories.

For example, every racehorse I’m aware of has its diet supplemented with alfalfa. Alfalfa aids horses with muscle weakness and reduces tying up caused by their high protein needs.

Foals and yearlings that aren’t getting enough protein either because their mother isn’t producing it in her milk or don’t suck should be fed alfalfa. However, feeding alfalfa to young horses is tricky because too much protein causes bone growth abnormalities. I suggest consulting your vet before feeding alfalfa to a young horse.

Here is a chart of the nutritional values of alfalfa hay as a percentage of dry matter:

Digestible Energy2.0 Mcal/kg
Vitamin A (IU)9,500
Vitamin E (IU)3.00

Please note that these values will vary depending on the growing conditions of the hay. It’s also important to note that the nutritional content of hay can change over time, so it’s best to use these values as a general guide.

Picture of bermudagrass hay next to alfalfa hay
Alfalfa next to bermudagrass hay.

Alfalfa is not good for all horses.

There are some downsides to feeding some horses alfalfa hay. You need to know the risks before deciding whether or not it’s safe for your horse to eat this type of forage.

As I mentioned above, alfalfa is good for working horses, but the opposite is true for non-working horses. Alfalfa will fatten horses, not burning the excess calories in alfalfa.

You shouldn’t feed horses with liver or kidney problems high protein diets, including alfalfa. It is also not a good idea to feed endurance horses too much alfalfa. Alfalfa provides high protein levels, which creates heat when it metabolizes, which isn’t good for endurance horses.

The heat requires horses to sweat more, drink more, and urinate. To combat these effects, only feed alfalfa as a supplement with grass hay. Also, horses diagnosed with HYPP (a genetic muscle disease prevalent in some quarter-horse pedigrees) should not be fed alfalfa or only in small amounts.

The high concentration of potassium in alfalfa can cause the symptoms of the disease to worsen. Horses who are allergic to ragweed should avoid alfalfa hay because they may have an allergic reaction.

Alfalfa hay can be expensive, but it’s worth the cost because it has such high nutritional value.

Currently, we pay about twenty dollars for a two-wire bale of alfalfa hay. That’s high when you consider a bale of Alicia hay sells for eight dollars. However, demand must be good even though I recently read that its popularity has declined because of its high price tag.

Among my family and friends, alfalfa’s skyrocketing prices have not deterred them from continuing to feed it. People pay such a high price because no other forage provides all the benefits you get in alfalfa.

Feeding alfalfa to your horse.

Your decision to feed alfalfa to your horse should be based on its need. To determine what to feed your horses, you should calculate how much digestible energy, protein, and calcium it needs.

Most lightly worked horses meet their daily nutritional requirement by grazing throughout the day. But what if a horse eats the same amount of alfalfa as grass per day?

As I stated earlier, a 1,000-pound horse eats about two percent of its body weight in grass or grass hay. If a horse eats two percent of its body weight in alfalfa, the excessive calories are converted to fat.

The abundant protein converts to ammonia and, along with the excess calcium, pass through the kidneys as urine. A horse continuing on a diet of only alfalfa hay would become obese and produce a lot of ammonia-smelling urine.

The best method is to feed alfalfa as a supplement with grass hay. Grass hay typically can’t meet the increased demand for horses’ energy when they are worked; this is especially true for racehorses, sport horses, and endurance horses.

For example, an average-sized horse in light work needs approximately 18.4 mega calories daily of digestible energy, 1.4 pounds of crude proteins, and 27 grams of calcium.

In 17.5 pounds of grass, hay provides 15.75 mega calories of digestible energy, 14 pounds of crude protein, and 39 grams of calcium.

These levels are a bit low for its daily needs of digestible energy, and to hit its daily requirements; you need to supplement its diet with grain, more grass hay, or alfalfa.

Now let’s look at the nutritional values for the same amount of alfalfa hay. In 17.5 pounds of alfalfa, you get 19.25 mega calories of digestible energy, 3.62 pounds of crude protein, and .24 pounds of calcium.

Alfalfa clearly provides more than the daily recommended amounts for all three. So it would be best for your horse in this situation to cut back on the alfalfa and substitute grass hay.

Picture of a 44 lb. bale of hay.

What is alfalfa?

Alfalfa hay is one of the most popular types of horse feed, but many misconceptions and myths surround it. We want to clear up some confusion by addressing those concerns.

Alfalfa is a perennial, a leafy green legume that is highly nutritious and a natural nitrogen source. It’s typically grown on farms for livestock consumption and as a soil conditioner. When making hay, the plant is harvested and cured before it reaches the flowering stage.

If the alfalfa plant is harvested too late, it becomes difficult for horses to digest. Also, it’s at its highest nutrient value when harvested early. Once it’s harvested and dried, it’s baled for storage until it’s ready to be used by farmers or horse owners.

High-quality alfalfa hay should be green with plenty of leafiness and have a pleasant smell, and the stems should be thin and pliable. Alfalfa is also available in cubes and pellets; either of these forms is easy to store and provides the same nutritional value as hay.


Does alfalfa make horses hot?

Alfalfa can make a horse hot if improperly fed. Alfalfa is high in protein and digestible energy (the net amount of energy an animal gets from its food), so you should feed it to horses that need the extra energy. Feeding it to a horse that’s locked up may cause it to get antsy, but if you regularly work your horse, feeding alfalfa won’t make it hot.

Does alfalfa cause colic in horses?

Alfalfa is rich and can cause colic in some horses. It is always a best practice to gradually change horses’ diet and introduce alfalfa by feeding it with grass hay.

Can alfalfa cause diarrhea in horses?

Alfalfa hay can cause diarrhea in a horse that overeats it because it is rich and full of nutrients. Overeating alfalfa can also cause a horse to have excess gas, develop laminitis, and founder.


Generally alfalfa is a good hay to feed horses, but there are caveats:

  • Don’t overfeed alfalfa
  • Only feed alfalfa if your horse needs extra digestible energy, protein, and calcium

However, from a practical standpoint, it’s best to feed alfalfa hay mixed with grass hay. As long as your horse is working at light levels, it benefits from eating small portions of alfalfa hay. But too much alfalfa can cause serious health issues.