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Key takeaways

Increased thirst (polydipsia) in horses describes an excessive amount of water intake. Normally, horses drink as much as 50 liters (13 gallons) of water per day.

  • Factors such as hot weather, sickness, pregnancy, and exercise can increase daily average water intake in horses
  • Water intake is considered polydipsia when horses drink up to double the average amount of water per day
  • The most common cause of polydipsia in horses is boredom
  • Other psychogenic factors such as stress or anxiety can also lead to polydipsia
  • Dietary factors are another possible cause
  • Kidney failure, metabolic horse syndrome, and Cushing’s disease are among the possible diseases leading to polydipsia
  • The diagnostic process focuses on eliminating other possible causes leaving only psychogenic polydipsia as the final diagnosis
  • Diagnostics include a physical examination, bloodwork, urinalysis, and diagnostic imaging
  • Treatment depends on the underlying condition but may include lifestyle changes, dietary management, and/or medications
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A closer look: Increased Thirst in Horses

Polydipsia is common in horses and is typically not a symptom of a life-threatening condition. Most of the time excessive water intake due to boredom or environmental causes.

In some cases, it can be an indicator of serious kidney disease or other underlying diseases and therefore still warrants a veterinary medical examination. Emergency medical care is required if signs of colic are also present.

Possible causes

Boredom is the most common cause of excessive thirst in horses. Horses often develop “stall vices” when their routine is too sedentary. Drinking too much is among the most common vices.

Risk factors

All horses are at risk of polydipsia if they do not have enough mental stimulation. Polydipsia as a medical symptom is expected to be accompanied by other symptoms. The presence of associated symptoms such as fever, weight loss, or lethargy might indicate a more severe condition.

Testing and diagnosis

The main goal of the diagnostic process is to rule out other possible causes leaving psychogenic polydipsia as the final diagnosis.

Diagnostics include:

  • A complete physical examination
  • Bloodwork
  • Urinalysis
  • Diagnostic imaging (usually ultrasound to assess the kidneys)

Treatment varies depending on the underlying condition. Usually, considering psychogenic causes to be the most common condition, treatment involves a change in daily routine and dietary management. Horses might respond well to a new companion, a different exercise routine, spending less time in the stall, or new toys. Other conditions might require medications or even surgery.

Similar symptoms

It is normal for a horse to drink more than the average amount of water under specific circumstances such as particularly hot weather, pregnancy, or after exercise.

Associated symptoms


David Ramey - Writing for David Ramey, DVM
No Author - Writing for Liphook Equine Hospital
No Author - Writing for Horse Side Vet Guide
No Author - Writing for Horse Side Vet Guide

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