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Is Alfalfa Bad For Horses?

Alfalfa Field

A rift has drifted through the horsing community. The discussion on alfalfa has become a battleground. “It’s got too much of this” or “not enough of that.” With the explosion of alfalfa production in the western United States, in some areas it’s become the only stored forage available. This has led to alfalfa being blamed (justly or unjustly) for many horse-related complications. The simple fact is that many horses are raised and perform each year on diets consisting largely of alfalfa. The real secret comes from understanding the benefits of alfalfa and knowing how to balance out its weaknesses.

The Protein Issue


80% of horses’ muscles and 20% of their skeletal systems are made up of protein. It’s the second major constituent of a horse’s body, water being the first. Protein is vital for a horse’s ability to grow, repair and form new tissue. It also plays an essential role in the formation of enzymes, hormones, blood solids and substances used in a horse’s immune system.

Generally the protein requirements for a horse decrease with age. Growing horses need more protein as they’re not just maintaining their bodies, but actually growing new bone and muscle mass. The exception to this rule is late pregnancies and lactation, when a mare has increased protein requirements to properly nourish her foal.

One of the biggest benefits of alfalfa is that it’s an excellent source of protein, both in content and quality. It’s not unusual for mid-bloom alfalfa to have a crude protein content of 17% or more. This can go a long way towards satisfying the high protein requirements of a young, growing horse. In the case of mature horses, free-choice alfalfa hay will certainly provide enough protein to satisfy requirements.

What happens if your horse gets too much protein? A horse’s body cannot store extra dietary proteins (amino acids). Instead, the excess protein is broken down and used as immediate energy or stored as fat. Protein that is broken down and used for energy has an added tax associated with the disposal of nitrogen. Contrary to popular belief, this by-product is not “hard” on a horse’s kidneys unless they’re already being overtaxed in some other way. It can take extra water to void nitrogen in a horse’s urine, so giving them access to H2O can be critical. As a practical recommendation, it’s best to avoid alfalfa hay with extreme levels of protein (greater than 17% crude protein).

The Mineral Issue


Today's horses are expected to perform at higher and higher levels, to mature more rapidly, to produce more offspring and to live a longer, more productive life than ever before. But this all comes at a price. To maintain these expectations, expended nutrients must be replenished. The problem is that forage doesn’t often have enough mineral content to meet a performing horse’s complex requirements, creating potential complications.

Alfalfa’s mineral content is largely dependent on the mineral content of the soil it’s grown in. The main issue arises when the mineral content of soil changes over time or from region to region. As a trend, today’s alfalfa crops generally don’t have the trace mineral profile to match the needs of a performing horse. If your horse is being fed strictly alfalfa hay, most experts recommend that you supplement their diet with additional trace minerals. These are typically in the form of pelleted grain concentrates or low intake mineral supplements.

Calcium and phosphorus are particularly important minerals for the skeletal formation of younger horses. While alfalfa is an excellent source of calcium, it generally falls short when it comes to phosphorus. The ideal calcium to phosphorus ratio for a young horse is between 1.5 to 2 parts calcium to 1 part phosphorus. In comparison, alfalfa hay generally has a ratio of 15 parts calcium to 1 part phosphorus. This is why experts recommend that young, growing horses receive supplemental phosphorus in the form of ration balancer supplements or “developing horse” commercial concentrates.

So is alfalfa dangerous to your horse? No, not if fed properly. Alfalfa’s availability and nutrient content make it a logical choice of feed. However, the key is to select alfalfa hay with moderate protein content and provide additional supplements to your horse when needed. Standlee Premium Western Forage® has several excellent choices of alfalfa products from pellets to cubes to compressed bales.

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