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Like many diseases common to people and animals, diabetes mellitus is a frequently diagnosed condition in pets, especially middle aged to older cats and dogs, and in dogs, it’s more common in females.

Diabetes mellitus results from failure of the beta cells in the pancreas to produce enough insulin. The pancreas is a small but critical organ attached to the upper small intestine near the stomach and liver. It has two functions – producing enzymes to aid in digestion and producing insulin to help the body utilise sugars, fats and proteins.

Pets develop the same types of diabetes as we do: Type 1 (genetic, this is rarely diagnosed in dogs and cats) and Type 2 (acquired, see predisposing conditions below. Certain breeds of dogs, including Australian terriers, beagles, Samoyeds, keeshonds, are thought to be more susceptible to Type 2).

What initiates diabetes mellitus?

Again, as in people, there are a number of predisposing conditions leading to Type 2 diabetes. Overweight dogs are more prone to diabetes. Dogs that have had pancreatitis – an inflammation of the pancreas – are also at higher risk of developing the disease. Certain drugs, including cortisone-type drugs and some hormones (especially those used for controlling oestrus) can initiate diabetes, especially if used for long periods. And other diseases in dogs, such as Cushings Disease (hyperadrenocorticism), can lead to diabetes.

Symptoms and clinical signs

When the body lacks insulin, sugar accumulates in the blood stream and excess spills into the urine. These high levels of sugar in the urine causes two key signs: polyuria and polydipsia. That is, the dog will begin to pass large amounts of urine and drink lots of water. The pet will be constantly hungry but at the same time, will lose weight as the nutrients in its diet are not being processed efficiently.

Other possible signs in dogs include cataracts, fat accumulation in the liver, and infections may develop in various organs.

Dogs with Type 1 diabetes will often show the key clinical signs (excess urination and drinking, and weight loss despite a good appetite) without being particularly unwell. Dogs with the more common Type 2 diabetes become seriously ill, and are often presented to CVH vomiting, weak and depressed.


Clinical signs of excess drinking and urination, backed up by the detection of high levels of sugar in the urine and blood, confirm a diagnosis of diabetes mellitus. A sweet odour may be noted on the breath if the animal is ketotic. A blood screen of other organs is essential to check for abnormalities in the liver, kidney and pancreas and diabetic patients with ketoacidosis may have an elevation in their blood stream of waste products that are normally removed by the kidneys.


Pets with diabetes require individual, carefully monitored treatment regimes. This usually includes 12-hourly insulin injections and always, a tailored, appropriate diet.

Undertaking treatment is a huge commitment for the pet owner. CVH vets give our clients as much information as possible – it’s essential the pet’s owner understands the requirements for successful treatment of diabetes before we begin the task of stabilising their dog for long term treatment.

The aim of treatment is to replace enough of the body’s insulin so clinical signs are controlled while avoiding low blood sugar (hypoglycaemia) from insulin overdose. It’s been said that the treatment of diabetes is a combination of art and science – each animal needs an individualised treatment regime, frequent reassessment and treatment modified based on response.

The insulin injections are given under the skin with very fine needles. Insulin dosing syringes are easy to use and allow accurate measuring of the small insulin doses required.

Diet modification

Managing the diet of diabetic dogs is critical and to make life easier, we stock both canned and dried prescription diets for diabetic pets. For overweight diabetic dogs, it’s essential to get the pet’s body weight back to normal – we can assist with helping to devise a safe weight loss diet. Alongside achieving weight loss is the need to feed a high protein/low carbohydrate diet. Protein provides a good energy source and prevents the loss of lean muscle mass, while feeding a diet low in carbohydrates is essential – carbohydrates can contribute to hyperglycaemia. Including high fibre levels in the diet is also helpful for controlling the weight of obese dogs. The frequency of feeds will also be important and this can include a regime of more frequent small meals given at specific intervals.

After the initial diagnosis

Once a diabetic pet is stabilised, successful ongoing treatment requires excellent teamwork and regular communication between the client and our vets. Clients need to become even more observant of their pet’s behaviour and health, learn how to monitor urine for sugar with dipsticks, and report any concerns promptly. It’s important to keep a daily record of injections and dose, water and food intake and appetite, the presence or absence of glucose in the urine, and to weigh your dog regularly. It’s also important to remember, while carefully managed, regular exercise is important for controlling weight in overweight dogs, strenuous and irregular exercise can cause severe hypoglycemia.

At CVH, we are well-experienced in the diagnosis and treatment of diabetes, but it is not an easy disease to manage and a successful outcome requires much dedication and patience from the pet’s owner. But it’s remarkable how many diabetic canine companions quickly become accustomed to their insulin injections, and go on to live happily for years after their diagnosis of diabetes.