As with humans, dogs find themselves thirstier than usual sometimes. However, if drinking is excessive or continues for multiple days then this could be the first sign that your dog is unwell. Adult dogs and cats are normally expected to drink around 50ml per kilogram of body weight each day; this includes water that they eat. Water balance is closely regulated by the body and many diseases can cause this to become unsettled. Increased drinking is often seen alongside increased urination; this can be a chicken and egg kind of situation as we try to figure out which symptom came first.
Increased thirst can be caused by a long list of diseases so we’d like to run through a few of these below.
- Dehydration – when the body has lost more water than it should, the brain detects this and triggers thirst. Water loss can be due to lack of access to water or from vomiting and diarrhoea.
- Fever – a raised body temperature will stimulate thirst as they lose water faster.
- Urine infection – cystitis can be very uncomfortable and causes increased urination which will in turn increase thirst.
- Kidney disease – kidneys are the gatekeepers of the water system, letting toxins and water out of the blood and into the urine. If the kidneys are diseases then they struggle to stop too much water being lost into the urine. This leads to dehydration and this makes your dog thirstier.
- Pyometra – female dogs that are not spayed are at risk of developing a womb infection. This can be fatal without treatment if the infection proceeds to septicaemia. Despite the infection, there is not always discharge from the vulva.
- Diabetes – high blood sugar levels cause the kidneys to be unable to stop excessive water loss in the urine. This leads to dehydration and thirst.
- Hormonal diseases – such as Cushing’s disease. During Cushing’s disease the body produces too much. This has many knock-on effects including increased thirst, increased urination, hair loss and enlargement of the abdomen.
If you have noticed that your dog has been drinking more than usual then please book an examination. It is also useful if you can measure how much your dog is drinking over 24 hours.