Question

I manage endurance horses. I have experience using alfalfa during races, but I have been told to not use it between races, when I'm training, as it could cause metabolic problems. Can you please tell me your thoughts?

Answer

Many performance horses benefit from alfalfa. The forage can be used successfully in endurance horses with some precautions.

At a competition, there is no better forage for endurance horses because of its palatability, high-calorie content, and nutrient profile. However, it is not usually fed to endurance horses as the only forage on a day-to-day basis.

The concern with feeding alfalfa daily is thought to lie in its high calcium content. The mechanism is not completely understood, but researchers believe that daily high calcium intake may affect the body’s ability to mobilize calcium during times of high need, such as those associated with long-distance competition.

The mechanism for calcium regulation (storage and mobilization) becomes “lazy” from lack of use when daily intake of calcium is high. When the need for calcium increases with prolonged exercise, the mechanism is slow to respond. The result can be low blood calcium, or hypocalcemia,, which can provoke early fatigue or thumps (synchronous diaphragmatic flutter).

Therefore, the recommendation for feeding alfalfa to endurance horses is to limit the amount fed on a daily basis but allow unlimited consumption at a competition. If you feel alfalfa would be helpful in maintaining weight on the horses in training, as long as it is fed at less than 30% of the total daily forage, it should not provoke hypocalcemia.