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Medical Index
First Posted: Nov 10, 2010
Jan 14, 2012

Urinary Infections in Horses

by Debora Johnson

Have you ever wondered what bacteria causes bladder infections in horses, how prevalent bladder infections are in horses, who gets them more male or female horses, what the symptoms may be, how does the vet diagnose a urinary tract infection and what may be causing the infections? The following may be of help.

The good news is that horses get less urinary tract infections than other mammals. The bad news is that if they get one and it is not diagnosed or treated it can have life threatening consequences. The lower urinary track infections are usually caused by the bacteria, E. coli. Proteus mirabilis, Klebsiella sp., Staphylococcus sp., Enterobacter sp., Corynebacterium sp., Pseudomonas aeruginosa and a fungus called Candida sp. Parasites are also known to cause urinary track infections in horses. Mares and young horses are more prone to urinary track infections than males. The reason for this is that females and young horses have a shorter distance from the skin to the bladder. However, often times these young horses have had other problems that needed heavy antibiotic treatment. Bladder infection in horses are usually caused secondary to other present infection. For example, there may be a skin or intestinal tract infection that has moved to the urinary tract. Once established and if not diagnosed, the infection can travel to the kidneys and become life threatening if not treated.

  • Painful urination
  • Humped back while urinating
  • Dripping urine
  • Blood in urine
  • Frequent attempts to urinate without success
  • Irritated skin around voiding area
  • Squirting of urine
  • Dribs and drabs of urine with repeated attempts to void

Call your vet to get a diagnosis if you have any concern. The vet is able to culture the urine. A catheter can be inserted to get a clean urine sample that has not been contaminated by any bacteria present on the horse's skin, etc. If bacteria is identified microscopically then treatment can begin.


Antibiotics will be prescribed by the vet. The antibiotic prescribed depends upon what bacteria or other culprit identified by the culture.

Other Potential Issues

Stones (urolithiasis) may be present in the urinary tract that can cause infection. The loss of muscle control in the bladder, also called a paralyzed bladder, can also cause infection. A nervous system disorder is usually the cause of a paralyzed bladder. Chronic renal failure, bladder rupture, polydipsia/polyuria, tumors, cancer, penile prolapse and other problems may also be considered.

Urinary Track Problems is an excellent comprehensive article that will answer most of your questions.

Medical Index