Acute kidney failure can occur when a kidney-toxic substance in the bloodstream causes direct damage to the kidney. In horses, it is more commonly a consequence of underlying intestinal disease (conditions causing colic) that cause dehydration and poor blood flow to the kidneys. This lack of blood flow itself can result in kidney damage. Tying-up (exertional rhabdomyolysis) is also a common precursor to acute kidney failure.

NSAIDs like bute and flunixin (Banamine) when given in excess, can cause renal failure in the horse. Young foals are even more at risk for these toxicities.

Horses in renal failure are depressed and lack appetite. They either urinate very frequently or hardly at all. Inability to excrete toxins cause them to build up in the bloodstream and make the horse feel ill. This is what causes depression and loss of appetite.

Veterinarians usually diagnose renal failure with routine blood work. BUN and creatinine are two commonly used indicators, as are other enzymes and electrolytes. Urinalysis is very helpful in assessment and management.

Buildup of waste products, called uremia, causes a whole host of problems in other body systems. Treatment is an attempt to reestablish kidney function. The mainstay of treatment is intravenous fluid therapy. In some cases, diuretics are used to stimulate urination.