Failure of the pancreas to produce enough insulin is thought to be the result of a combination of factors. It is considered some animals have an inherited predisposition to both a lack of insulin producing cells (ß islet cells) or sensitivity to other causes of islet cell damage. These other causes include viral infections, toxins, and chronic stress which may trigger an allergic over reaction around the cells causing their destruction. Most commonly diabetes occurs between 4 and 14 years of age with females being effected at twice the rate of males.

Clinical signs classically include increased drinking (polydypsia), increased urination (polyuria), and weight loss with normal to increased appetite. Less commonly secondary cataracts ( whitening of the lens in the eye) may occur. As the condition progresses the animal may become generally ill with vomiting, dehydration, and severe depression. This is a result of the body breaking down its fat reserves to try to compensate for its inability to absorb glucose. The breakdown of the fats produces byproducts called ketones which can be toxic to the body at high levels This situation is called ketoacidosis.

The kidneys pump out the excess sugar which also drags out large amounts of fluid leading to the polydypsia and polyuria. Identifying high levels of glucose in urine samples (glycosuria) can be use to diagnose diabetes however blood tests give a more accurate assessment of the condition. Ketones can also be detected in both blood and urine.

Treating diabetes has both short term and long term considerations. Insulin replacement therapy is the basis of most treatment regimes however not all animals will respond to insulin. Where the underlying problem is a failure of the insulin receptors in the body's' cells, the level of insulin being produced by the pancreas may already be normal. Animals with ketoacidosis must also be stabilized using intravenous fluids (a drip) and sometimes potassium supplementation. Any underlying disease states such as pancreatitis must also be identified and corrected.

Insulin replacement therapy requires a dose of insulin to be injected under the skin either once or twice each day at set times depending on the type of insulin being used . Measured amounts of food are then given at set times to coincide with the peak action of the insulin. Animals are usually hospitalized while a suitable insulin treatment level is established, as this requires regular measurement of blood sugar. At home periodic urine glucose sampling can be used to monitor the diabetic animal. Overdoses of insulin will cause the blood sugar to drop below a level the body can tolerate (hypoglycemia) producing convulsions and collapse. This is an emergency situation.

Long term complications can result from any illness which reduces food intake, hormonal changes such as coming into season, and gradual development of resistance to the insulin.