Bovis ISSN 2398-2993

Water intoxication

Synonym(s): cold water hemoglobinuria, acute dilutional hyponatremia

Contributor(s): Nicola Bates , Alessandro Seguino

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  • Cause: rapid ingestion of water following a period of water deprivation.
  • Signs: hemoglobinuria and neurological signs.
  • Diagnosis: history (water deprivation followed by unlimited access to water) and neurological signs.
  • Treatment: usually no intervention for mild to moderate cases. Intravenous hypertonic saline and furosemide can be given in severe cases.
  • Prognosis: good for mild cases; guarded in animals with pronounced neurological signs.



  • Dilutional hyponatremia can occur after ingestion of water at a rate in excess of the maximal excretory capacity of the kidney, or by ingestion of lesser amounts of water with impaired water excretion by the kidney.  
  • Water intoxication occurs following rapid ingestion of water and may occur under several circumstances:
    • Following a period of water deprivation.
    • Following strenuous exercise.
    • During periods of high environmental temperatures.

Predisposing factors


  • Water intoxication can occur in calves offered free access to water for the first time.
  • Bucket-fed calves usually drink excessive water if it is offered in the manner in which they normally receive their milk.
  • The volume ingested is limited by the capacity of the gut not by satiety and the rumen can hold a large volume of water compared with total body size.
  • Chronic subclinical dehydration with increased environmental temperature, excess of fluid loss due to diarrhea or fever may predispose to water intoxication.
  • Calves with oliguria or calves that fail to develop diuresis soon after water overload at are also at risk.
  • Failure to provide both water and salt before weaning also predisposes to water intoxication.

Adult cattle

  • Free access to water following a period of water deprivation. Even a short period of water deprivation (eg 1 day) followed by free access to water can result in water intoxication.


  • Ingestion of too much water results in a positive water balance which leads to hemodilution.
  • Water retention causes a dilution of body solutes and a reduction in osmolality.
  • There is a rapid fall in serum sodium which results in increased water uptake by cells. This has multiple effects:
    • Edema in the brain resulting in neurological signs.
    • Hypotonicity of erythrocytes causes lysis resulting in hemoglobinuria and anemia.


  • Onset is often rapid (<30 minutes) but can be longer (eg several hours).
  • In mild cases recovery may occur in 3-4 hours, particularly if there is rapid diuresis after ingestion of excess water.
  • In more severe cases recovery can take 2-5 days.
  • Death generally occurs within 24-72 hours, but can occur within a few hours.


  • Water intoxication is a particular risk in hot weather when drinking water is limited or absent and then freely available.
  • Water intoxication also occurs following a long transport period without access to water followed by rapid ingestion of water on reaching the final destination.


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Further Reading


Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Aitra S, Berisso R & Quiroga M A (2017) Intoxicación hídrica en Bovinos. [Water intoxication in cattle]. [online]. Thesis, Faculty of Veterinary Sciences, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Argentina. Available at:
  • Kawahara N, Ofuji S, Abe S, Tanaka A, Uematsu M & Ogata Y (2016) Water intoxication in adult cattle. Japanese journal of vet research 64 (2),159-64 PubMed.
  • Njoroge E M, Maribei J M, Mbugua P N & Njiru S M (1999) Water intoxication in cattle. Journal south african vet 70 (4), 177-9.
  • Maribei J M, Njoroge E M & Mbungua P N (1998) Clinical manifestation of experimental water intoxication in calvesIndian journal animal sci 68 (6), 531-2 VetMedResource.
  • Njoroge E M, Maribei J M & Mbugua P N (1997) Pathological changes in calves that died from experimental water intoxication. Onderstepoort journal vet res 64, 111-114 PubMed.
  • Gilchrist F (1996) Water intoxication in weaned beef calves. Canadian vet journal 37 (8), 490-1 PubMed.
  • Shimizu Y, Naito Y & Murakami D (1979) Experimental study on the mechanism of hemolysis on paroxysmal hemoglobinemia and hemoglobinuria in calves due to excessive water intake. Japanese journal vet sci 41 (6), 583-592 PubMed.
  • Gray T C (1970) Dehydration and water intoxication of range cattle. AVMA 157 (11), 1549-56 VetMedResource.
  • Kirkbride C A & Frey R A (1967) Experimental water intoxication in calves. AVMA 151 (6), 742-6 PubMed.
  • Lawrence J A (1965) Water intoxication in calves. SAVA 36, 277-278.