Question: My horse’s urine appears red in the snow. My horse seems healthy, but should I be concerned (see photo)?
Response: Horse urine can change color after being voided due to the presence of plant metabolites (pyrocatechines) in the urine that turn a red or orange color when mixed with oxygen. This can happen year around, but is especially noticeable in snow. This can also be noticeable in new, light-colored shavings. Normal horse urine appears colorless to yellow to dark yellow when voided. If the urine appears red, brown, or orange as it is being voided that can indicate a serious problem and your veterinarian should be called immediately.
Bottom line, if horse urine is an abnormal color as it is being voided or you observe frequent urination or straining to urinate call your veterinarian immediately. If your horse is passing normal colored urine that turns red or orange in the snow, that is normal.
This article is reprinted with permission from Krishona Martinson, University of Minnesota. This and other horse nutrition articles can be found at http://www.extension.umn.edu/agriculture/horse/nutrition/.