Hepatic Lipidosis in Horses

Hepatic Lipidosis in Horses

Early signs of hepatic lipidosis, such as lethargy and weakness, often are overlooked because of their vague nature.

Photo: Erica Larson, News Editor

Although liver problems in horses are relatively uncommon, one every horse owner should be familiar with is hepatic lipidosis. This dangerous condition, in which fat deposits into the liver, is fatal in up to 80% of horses that develop it. And although hepatic lipidosis is most common in Miniature Horses, ponies, and donkeys, the ailment can affect horses of all shapes and sizes.

Philip J. Johnson, BVSc(Hons), MS, Dipl. ACVIM, ECEIM, MRCVS, a professor of equine medicine and surgery at the University of Missouri's College of Veterinary Medicine, delivered a presentation about the condition at the American Veterinary Medical Association Convention, held July 16-19 in St. Louis, Mo.

Hepatic lipidosis is a condition often prompted by a change in a horse's eating habits. When a horse stops eating or drastically reduces the amount of feed he consumes (often the result of another factor such as colic or stress) his body does not get the energy it needs to carry out daily functions, as energy comes from converting food into glucose. When this happens, the body tends to find another source of energy. In some cases the body will mobilize fat into the blood stream and send it to the liver to convert it into glucose. As fat builds up in the bloodstream, the liver, and other related organs, the horse's body stops functioning properly.

When the liver is overcome with fat and isn't able to clear toxins out of the blood, the horse often feels uncomfortable and will typically reduce feed intake even further. This lack of consumption simply adds to the problem, increasing the amount of fat circulating through the bloodstream and into the liver.

Johnson noted that early signs of the disease, such as lethargy and weakness, often are missed because of their vague nature: "Usually, it is not obvious in the beginning what is happening. The animal is simply lethargic and stops eating, and people tend to take a wait-and-see attitude. But a sudden discontinuation of food intake might precipitate hepatic lipidosis with dire consequence."

As the disease progresses, additional clinical signs include those indicative of liver failure, such as jaundice, staggering, weakness, leaning, falling, colicky behavior, and recumbency.

If treated early, veterinarians can sometimes help the horse recover with a relatively straightforward treatment regimen aimed at correcting the underlying cause of the problem and encouraging the horse to resume eating voluntarily. The main goals of therapy are to restore the energy balance by addressing the primary condition and encouraging the horse to eat. Patients require intensive care, intravenous fluids, and nutritional support, as well as other medications. Still, between 40% and 80% of affected animals die as a result of the disease.

Johnson noted that obesity is a major risk factor for the disease and advised owners to keep close tabs on their horse's body weight: "Miniature Horses (along with ponies and donkeys) are often plumper than they should be," he explained. "Obesity is certainly a risk factor for this condition, although they don't have to be obese to get this condition."

Females are more prone to develop hepatic lipidosis than are males, Johnson added, and pregnancy, delivery, and nursing can all contribute to an increased risk of developing the condition. Often, a vigorously feeding foal will trigger the problem, as a mare won't have enough energy to keep up with the foal's nursing demands. Johnson discussed one such case in which a 12-year-old Miniature Horse's foal was a "dangerously energetic" feeder. The mare had been off her feed for three days before she was treated and, although she was severely dehydrated, depressed, and weak, Johnson's team finally got her eating normally again and she survived her bout of hepatic lipidosis.

Keeping equids at a healthy body weight and monitoring their feed intake closely can help owners prevent hepatic lipidosis. Should a horse go off his feed, seek veterinary attention to ensure the horse is not suffering from hepatic lipidosis or any other potentially dangerous medical condition.

About the Author

Marie Rosenthal, MS

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