Minerals are involved in numerous functions in the horse’s body, including the function of enzymes, structural components, energy transfer and acid-base balance. Minerals are also components of vitamins, amino acids, and hormones. The minerals that are needed in the largest quantities by horses are referred to as macro-minerals.¹ These include calcium (Ca), phosphorous (P), magnesium (Mg), potassium (K), sodium (Na) and chloride (Cl).

The skeleton accounts for 99% of the calcium in a horse’s body, however, this mineral is also essential for neuromuscular function, blood clotting, cell signaling and other functions. Because of its importance, calcium concentrations are very efficiently regulated in the bloodstream. When calcium in the diet is inadequate, the bones serve as a reservoir, with the body sacrificing calcium within the bone to maintain blood calcium homeostasis. 

A prolonged period of calcium deprivation as described above will lead to a weakened skeleton. This also means that the horse’s calcium blood values will be poor indicators of actual calcium levels in the horse. Calcium deficiencies can lead to osteopenia, a loss of bone mineral density. This can be especially detrimental to growing horses and performance horses.¹Calcium deficiency can also lead to metabolic bone disease (MBD), which presents with a variety of bone disorders.²

Signs of calcium deficiency in a horse may include:

• Poor hoof quality
• Uneven movements (“shifting lameness”)
• Bony lumps
• Shin soreness
• Fractures under stress
• Poor quality of teeth
• Osteoporosis
• Arthritis
• Weight loss
• Depression
• Stiff appearance
• Shortened gait when trotting

Adult non-performance horses have lower calcium requirements than growing, performance or working horses. The increase in calcium requirements for exercising horses is believed to be due to an increase in bone deposition.¹Performance horses typically experience an increase in bone mass related to exercise demands and thus have a greater need for calcium.

Causes of Calcium Deficiency in the Horse

Horses typically get calcium from their diet. This is impacted by several other factors, however. Other minerals can affect the bioavailability of calcium in the horse’s body. If there is too much phosphorus in the horse’s diet, for example, this will interact with calcium in the small intestine and lead to less calcium being absorbed. Too much calcium in a horse’s diet can prevent the horse from absorbing copper, manganese, zinc and iron. If there is too much zinc in the horse’s diet, the surplus zinc can prevent the horse’s small intestine from absorbing calcium. 

Oxalates can also decrease the amount of calcium that is available to a horse, thereby bringing about a calcium deficiency, and some plants found in pastures have high amounts of oxalates.²

Plants that contain oxalates include:

• Alfalfa
• Halogeton (Halogeton glomeratus)
• Shamrock
• Rhubarb

Thus, it is important to ensure that horses not only ingest the proper vitamins and minerals they need (and enough of them), but these must also be balanced. They must also be given in amounts that compensate for any potential losses as described above.

Where to buy Calcium Levulinate

Calcium levulinate is available in the U.S. through pharmaceutical manufacturers and through veterinary custom compounding companies. 

Please consult your veterinarian prior to beginning any treatment regimen.

FOR RX ONLY: A valid prescription from a licensed veterinarian is required for dispensing this medication.

¹wagwalking.com.

²okstate.edu.