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Lipomas: Hidden Dangers of Obesity in HorsesBy Kentucky Equine Research Staff · May 1, 2017

The effects of obesity among horses and ponies are generally obvious to the naked eye: a rotund, physique, often with a cresty neck; labored breathing at even the mention of exercise; and ponderous, awkward movement, and perhaps unsoundness, when asked to move. One possible and unnoticeable result of chronic overfeeding is the development of lipomas, benign tumors within the abdominal cavity that originate from adipocytes or fat cells.

Lipomas are not typical in young horses; rather, they usually affect horses at least 10 years of age. The reason for this is simple: lipomas are thought to be slow-growing neoplasms that sometimes require years to become sufficiently large enough to cause problems.

While the actual lipoma is benign, the position of the growth within the abdominal cavity often creates havoc. Lipomas grow on stalks, and these stalks can wrap around a segment of intestine, triggering strangulation of the soft tissue and leading to obstructive colic. Strangulating lipomas generally affect the small intestine, small colon, and occasionally the rectum.

Surgical removal of the lipoma and strangulated loop of intestine is possible, and long-term survival of the affected segment is thought to be about 40-50%*, according to one retrospective study, though other studies indicate a higher rate of survival.

Horses of all body types are often diagnosed with lipomas, so these tumors should not be considered merely a “fat-horse” ailment. However, it is best to maintain horses in moderate body condition. Keeping horses in fair, not excessive, flesh has many benefits, primary of which is optimal health to perform the tasks asked of it with minimal wear and tear. To maintain horses in reasonable body condition, follow these tips:

  • Assess weight often. Body condition can be evaluated during an ordinary grooming session. Feel for ribs along the horse’s barrel. The ribs of a horse in moderate body condition will be well covered by flesh and fat but are easily felt. If the ribs are buried deep in tissue and are difficult or impossible to feel, then your horse is likely carrying too much weight.
  • Feed to meet energy requirements and no more. Once your horse achieves moderate weight, you should feed the horse to preserve that weight. This might prove to be a trial-and-error endeavor, but regular scoring will keep you on the right track. An equine nutritionist can help you formulate a diet that matches your horse’s nutritional needs and metabolism.
  • Include exercise as part of a horse’s lifestyle. Horses benefit tremendously from exercise, whether it’s being ridden, driven, longed, ponied, or otherwise worked. Exercise is so important that it is extolled as a vital component in sidestepping metabolic issues. Thirty minutes of exercise nearly every day will help excess weight from accumulating. This exercise should require the horse to do more than walk casually along a flat expanse; varying gaits and terrain will be most beneficial, so long as soundness is not an issue.

*Blikslager, A.T., K.F. Bowman, M.L. Haven, et al. 1992. Pedunculated lipomas as a cause of intestinal obstruction in horses: 17 cases (1983-1990). Journal of the American Veterinary Medical Association. 201:1249-1252.