Some dogs are naturally more thirsty than others… But do you know how to tell when this could be a sign of an underlying problem?
Why do dogs get thirsty?
The drive to drink is controlled largely by the concentration of the blood. If the concentration is too high they start to feel thirsty (as a result of increased fluid loss) meaning that the dog must drink more to compensate.
So, what can cause an increased thirst?
There are a wide range of common conditions that can make a dog more thirsty than usual. They include:
Dehydration – This is the most common reason and causes include:
- Not having access to sufficient water.
- Fluid loss due to vomiting or diarrhoea
Fever – A raised temperature due to an infection will make dogs more thirsty, in addition they lose water and become dehydrated.
Kidney disease – Kidneys work to maintain the body’s fluid balance. If the dog is dehydrated the kidneys will reduce water loss, whereas if the dog is overhydrated the kidneys increase water loss. If the kidneys are damaged they progressively lose this capacity. This results in the inability to concentrate urine which increases fluid loss.
Certain drugs such as steroids alter the way the kidneys process water, increasing urination and also driving increased thirst.
Cushing’s Disease – This hormonal condition means that the dog’s body produces excessive quantities of natural steroids – with the same result as the steroid drug.
Pyometra – A womb infection in a bitch often presents initially with increased thirst. It generally progresses to lethargy, vomiting and septicaemia and may be fatal without treatment.
Diabetes mellitus (sugar diabetes) – This is a common hormonal disease in dogs and occurs when the dog cannot regulate their blood sugar levels. As the blood sugar level increases it eventually exceeds the level that the kidneys can maintain, resulting in glucose passing in the urine. This leads to increased urine output, dehydration and increased thirst.
Diabetes insipidus (water diabetes) – This is a rarer cause of increased urination, and is a different type of diabetes. Sugar diabetes results from failure of the hormone insulin, whereas water diabetes occurs if the dog is unable to produce the hormone vasopressin. Insufficient vasopressin levels result in excessive urination and hence dehydration.
Psychogenic Polydipsia – This is a behavioural disorder that isn’t well understood. Essentially, the dog is drinking too much just because they like to drink. Fortunately, it isn’t harmful, but can only be diagnosed by ruling out all other possible causes.
So how much SHOULD my dog be drinking?
Most dogs drink about 50ml per kg bodyweight per day, including the water in their food. We wouldn’t normally worry until they were drinking more 90ml per kg bodyweight per day or if their thirst suddenly increases.
If you are concerned that your dog is drinking too much please make an appointment to get them checked out by one of our vets. If you are not certain if you should be worried or not please ask to see or speak to one of our Registered Nurses who can advise you if further intervention is necessary. The earlier any problem can be diagnosed, the better the outcome is likely to be.