MSD Manual

Please confirm that you are a health care professional

honeypot link

Hypercalcemia in Horses


Mark E. Peterson

, DVM, DACVIM, Animal Endocrine Clinic

Last full review/revision Jul 2013 | Content last modified Jul 2013

Like dogs and cats, horses can develop hypercalcemia due to several disorders, including chronic renal failure, vitamin D toxicosis, and primary hyperparathyroidism. The most common cause of hypercalcemia in horses is chronic renal failure. The equine kidney is important in the excretion of calcium; therefore, impaired renal calcium excretion associated with normal intestinal calcium absorption may explain the hypercalcemia found in these horses.

Humoral hypercalcemia of malignancy has been reported to be associated with gastric squamous cell carcinoma, adrenocortical carcinoma, squamous cell carcinoma of the vulva, lymphosarcoma, and ameloblastoma. These horses have hypercalcemia, hypophosphatemia, increased serum concentrations of PTHrP, and decreased serum concentrations of PTH.

Intoxication with ergocalciferol or cholecalciferol has been reported in horses. Ingestion of plants containing 1,25-dihydroxyvitamin D–like compounds (Solanum malacoxylon, S sodomaeum, Cestrum diurnum, Trisetum flavescens) causes typical clinical signs of vitamin D intoxication, including hypercalcemia.

Primary hyperparathyroidism is a rare disorder in ponies and horses. As in dogs and cats, hypercalcemia, hypophosphatemia, and high serum PTH concentrations are reported in horses with the disorder. Additional tests to exclude other conditions associated with hypercalcemia may include measurement of PTHrP and vitamin D metabolite concentrations.

As in other species, the definitive treatment of equine hypercalcemia is treating or removing the underlying cause. Unfortunately, the cause may not be readily apparent, and supportive measures (eg, fluid therapy, diuretics, and/or glucocorticoids) must sometimes be used to enhance urinary excretion of calcium and to decrease the serum calcium concentration.

Others also read
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Test your knowledge
Disorders of Calcium Metabolism
Calcium, in its ionic form, plays a key role in the function of many body systems. Precise control of calcium ion concentrations in extracellular fluids is regulated by several hormones. Which of the following is NOT involved in calcium homeostasis?
Become a Pro at using our website 

Also of Interest

Become a Pro at using our website