Horse Side Vet Guide ®

Equine Health Resource

Diabetes Mellitus

Synonyms: Insulin Dependent Diabetes

Cells (beta cells) within the pancreas produce the hormone insulin, which is vital to normal metabolism. Diabetes mellitus (insulin-dependent diabetes) is failure of these cells to produce insulin for any reason.

True insulin dependent diabetes is very rare in horses. Much more common is inhibition of insulin function by cortisol in horses with PPID (Cushing’s Disease).

Cases occur when the pancreatic cells are destroyed from pancreatitis or pancreatic cancer. There have been reports of parasitic migration into the pancreas, causing pancreatitis and destruction of Beta Cells. Diagnosis requires oral or IV glucose tolerance test.

The only treatment for true insulin dependent diabetes is administered insulin (given by injection as in human diabetics).

Author: Doug Thal DVM Dipl. ABVP


Higgins AJ, Snyder JR eds. The Equine Manual. 2nd Ed. Edinburgh: Elsevier Saunders 2006.


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