Liver disease is not uncommon in horses and plants in the pasture are a common source of liver disease. The most common symptoms of liver disease include icterus, which is yellowing of the mucous membranes; poor body condition; decreased appetite; lethargy and intermittent colic. Liver disease can be caused by ingesting plants that contain a chemical called a pyrrolizidine alkaloid. Although these plants are generally not consumed by horses, small amounts over the life of the horse can lead to toxicity. The plants also remain toxic even in hay and with the drought we have had in many states this last year, horses have been forced to eat feeds they would not normally eat.

Liver toxicity has also been reported by horses eating alsike clover and red clover. Other kinds of clover are not toxic to horses but be aware of buying hay that has clover in it; be sure of the type of clover. Ingesting this type of clover can cause acute or chronic signs of liver disease with symptoms of depression, lethargy, lack of appetite and jaundice. Another plant that can contribute to liver disease in horses is fall Panicum that can be found in hay and symptoms are similar to those found with other toxic liver diseases.

To diagnose liver disease, blood tests are helpful but a liver biopsy is required to determine the severity of the disease. Treatment of liver failure in a horse requires supportive care such as fluid therapy and a low-protein high-energy diet. Because some plants can cause skin disease if a horse with liver disease is out in the sun, it is a good idea, at least initially, to keep all horses with liver disease in covered areas.