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Equine Health Resource

Urine appears Dark Yellow

Code Green - Contact Your Vet to Obtain Useful Advice & Resources

Code Green - Contact Your Vet to Obtain Useful Advice & Resources

  • If you have questions about how management or feeding might affect this.
  • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.

Dark urine is usually a sign of urine concentration, the body’s natural way of conserving water. When the blood pressure is low, the kidney pulls back as much water from the filtered urine as possible, making it less dilute.

Dehydration is the most common cause of this observation, however any disease process that causes reduced blood flow to the kidneys will also have this effect. This observation can also be confused with urine that is stained dark brown by the presence of myoglobin, a muscle pigment shed into the blood when muscle cells are damaged. In most cases, horses with myoglobin in their urine have “tied up”.

Horses tend to drink less water in the winter, especially if their water is not heated. Consider providing a heated water source to horses wintering in cold climates. Always provide a white salt source. If the problem persists, consider talking to your vet about stimulating thirst with supplemented oral electrolytes.


Always provide plenty of access to fresh, clean water. You may monitor your horse for awhile and contact your vet if your horse’s urine color does not return to normal or is decreased in volume.

Assess your horse’s general health using the Whole Horse Exam (WHE), paying particular attention to heart rate, hydration with skin pinch on the shoulder, mucous membrane color and capillary refill time, and general attitude and appetite. If the horse shows any other signs of illness, such as depression or not eating, involve your vet right away.


Your vet rules out disease conditions using a combination of physical exam, blood work and urinalysis.

Author: Doug Thal DVM Dipl. ABVP


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