How your horse’s liver functions


Although organ failure is rare, horses can easily develop liver disease.


A healthy liver is vital to your horse’s overall well-being. This organ is responsible for many of the functions that keep your horse going. It helps with digestion and removes toxins from the body. Unfortunately, it’s easy for a horse to accidentally eat foods that damage the liver, which could lead to organ failure.

Horses can develop liver disease by eating toxic plants.Horses can develop liver disease by eating toxic plants.

Understanding liver function
While a horse’s liver accounts for less than 2 percent of its body weight, according to TheHorse.com, it holds 10 percent of the animal’s blood supply. The liver filters toxins from the blood, but it also means the organ is highly susceptible to certain contaminants. In addition to cleansing blood, a horse’s liver produces and secretes bile, synthesizes certain proteins and helps metabolize fats, fatty acids, sugar, glycogen, proteins and carbohydrates.

Because the liver is vital for so many bodily processes, failure can be deadly for your horse. Thankfully, cases of actual liver failure are rare – a liver can continue functioning until about 70 percent of it is damaged.

Liver disease, on the other hand, is much more common and should be addressed immediately. One common cause is the accidental ingestion of toxins – essentially, your horse might eat a poisonous plant. Tri-State Livestock News spoke with Dr. Jared Janke of Sturgis Veterinary Hospital, who pointed to pyrrolizidine alkaloids as the most commonly ingested toxin. PAs can be found in pastures and, on occasion, in feed. PA is present in a wide variety of plants, including prairie ragwort, Riddell’s ragwort and other members of the Senecio family, a genus easily found in the U.S.

“There are at least 17 species of Senecio on the Great Plains,” Dr. Janke told the publication.

“If a horse eats 2 percent of its weight in toxic plants, liver failure can occur.”

Consuming PAs is often deadly, according to TheHorse.com. When ingested, the toxin either kills liver cells or causes them to divide. If a horse eats too much, about 2 percent of its body weight, liver failure can occur. Horses generally find plants with PA unpleasant to the taste, but weather extremes like droughts make them easier to tolerate. PAs are also hard to avoid when baled in hay. Because they can scar the liver, it’s hard to reverse any consequent damage.

Other poisonous plant species include witchgrass, kleingrass and switchgrass. Mycotoxins and aflatoxins, found in moldy feeds, can also harm the liver.

Diagnosing liver disease 
According to the Merck Veterinary Manual, symptoms of liver disease include jaundice, weight loss, colic, depression and a decreased appetite. Your horse might also become sensitive to ultraviolet sunlight and, therefore, more susceptible to sunburns. Constipation, diarrhea and harsh, high-pitched breathing can also signal liver disease, but these symptoms are far less common than the others.

Liver disease is easy to spot through a routine blood screening. While a test can’t measure how well your horse’s liver functions, elevation of certain enzymes like GGT and bilirubin can indicate liver problems. These two in particular, along with ALP, point to issues with the biliary tract. In addition, a horse with an inflated tract will have greenish-orange urine, TheHorse.com noted. If blood work points to liver disease, your veterinarian might perform an ultrasound or liver biopsy. The latter will tell whether the disease is acute or chronic and point to any underlying causes.

As always, prevention is key to keep your horse from developing liver disease. Equine supplements with lipotropes like folic acid, vitamin B12 and Lecithin (and hydrochloride) can support healthy liver functions. In addition, make sure your horse doesn’t ingest any toxic plants. Learn which species are common in your area so you know what to avoid.  Research Associates’ product, Livatrope helps promote healthy liver function in the horse.