Increased Urination in Horses

Published on
Last updated on
3 min read

Key takeaways

Increased urination is excessive passing of urine either in frequency (pollakiuria) or volume (polyuria).

  • In a healthy adult horse, the normal amount of urine is about 8-9 liters (2.5 gallons) per day
  • Frequent or excessive urination can be a sign of many bladder, kidney, or urethral conditions, as well as endocrine (hormone) disorders
  • Frequently associated conditions include Cushing’s disease, metabolic horse syndrom, kidney failure, neurological dysfunctions of the bladder, bladder or urethral inflammation, and colic
  • The diagnostic process includes a thorough history and physical examination; bloodwork, urinalysis, and diagnostic imaging may also be required
  • Treatment varies widely depending on the underlying condition
  • Less complex cases may respond to dietary changes and behavioral therapies
  • More severe cases may require dialysis, medications, and/or supportive care
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A closer look: Increased Urination in Horses

Both polyuria and polydipsia are common in horses. Usually, increased urination is not a life-threatening symptom. It is important to determine the cause as soon as possible, especially when other symptoms are present such as decreased appetite and weight loss, or changes in the scent and color of urine.

Increased urination can also coincide with colic. Colic often appears with other symptoms such as abdominal pain, restlessness, lip curling, and rapid breathing and is an emergency. Red urine might also indicate an emergency and can be present in horses with increased urination.

Possible causes

Risk factors

The volume and the frequency of urination can vary and might be an indicator of the severity of the underlying condition. The color of the urine can also vary and be an indicator of the underlying condition. With chronic kidney disease, the kidneys are no longer able to produce concentrated urine, which has a deep yellow color. Poorly concentrated urine looks like water and might be an indicator of kidney dysfunction.

Red urine is also a concerning sign as it is associated with more serious conditions such as urinary stones, urinary tract infections, severe muscle damage, and life-threatening cancer.

The presence of other symptoms might be an indicator of a more serious condition.

For example, rapid breathing, abdominal pain, restlessness, and lip curling are some of the associated symptoms of colic; and weight loss, loss of appetite, and changes in smell or color of the urine are associated with chronic kidney disease.

Testing and diagnosis

As one of the most common causes of increased urination is an excessive amount of water intake due to boredom, or psychogenic polydipsia, the diagnostic process begins by ruling out other diseases.

Diagnostics involve bloodwork and urinalysis. Other tests, such as diagnostic imaging of the bladder and the kidneys might be necessary.

Treatment depends on the underlying cause. In most cases, polyuria is due to external causes such as drinking too much water, diet, boredom, or other environmental reasons. A dietary change is often recommended, as well as a change in lifestyle. More severe conditions, such as metabolic horse syndrome or kidney failure, might require dialysis, medications, or lifelong monitoring.

Similar symptoms

When in heat, mares usually urinate more frequently. Polydipsia (increased thirst) leads to horses drinking excessive amounts of water and as a consequence expelling more urine than normal.

Associated symptoms


Editors of EQUUS - Writing for EQUUS Magazine
No Author - Writing for Horse Side Vet Guide
No Author - Writing for Liphook Equine Hospital
David Ramey - Writing for David Ramey, DVM
No Author - Writing for Merck Veterinary Manual
Emily A. Barrell DVM, MSc - Writing for Veterinary Clinics of North America: Equine Practice
Stacey Oke, DVM, MSc - Writing for The Horse

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