What does brownish-green urine indicate in a horse?

Brownish-green urine in a horse is often indicative of jaundice. Jaundice, or icterus, is a condition that arises from an excess of bilirubin in the blood, which can lead to the urine taking on a darker color. Since bilirubin is a byproduct of the breakdown of red blood cells, when the liver is unable to process it adequately, the elevated levels can affect urine coloration.

Other factors such as dehydration, kidney damage, and urinary tract infections often influence urine color as well, but they do not typically result in a brownish-green hue. Dehydration may lead to darker urine, while kidney issues frequently result in changes that indicate decreased urine output but do not specifically change the color to brownish-green. Urinary tract infections could affect color too, but they are more often associated with discoloration towards cloudy or yellow tones rather than the specific brownish or greenish tones seen with bilirubinuria related to jaundice. Thus, the presence of brownish-green urine is most closely associated with the liver's inability to process bilirubin, reinforcing the connection to jaundice.