Health Care

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Hindgut Ulcer

Have you heard the term “Hindgut Ulcers”? Know what they are? Read on to find out more.

Almost every horse owner has heard the term “hindgut ulcers”. However, there are no reliable tests for hindgut ulcers and there is very little science to suggest they are actually a problem in horses. Whilst “ulcers” are very common in the stomach they are rare in the hindgut. A recent (2017) study1, performed at the University of Glasgow set out to look specifically for hindgut ulcers. The investigators looked at the gross pathology of lesions on the mucosal surface of the equine large intestine. The large intestine of these horses was examined immediately the following euthanasia and they found that colonic ulceration was only present in 21% of horses. Small strongyles (cyathastomins) and tapeworms were the cause of more than 50% of the lesions, a small number were caused by sand and about 25% were due to unknown causes.

But what and where is the hindgut?

The equine hindgut, or large intestine, consists of the following segments: the caecum, large colon, small colon and rectum. The hindgut of horses is approximately 7.5-8.0m long and is where most of the microbial digestion of feed and reabsorption of water occurs. Once food leaves the stomach, it travels through approximately 15-20m of small intestine before it reaches the hindgut. As a result, there is no way to check for hindgut ulcers during a gastroscopy as most endoscopes are only 3m long.

horse gastric ulcers risks and signs

So, where does that leave us?

  1. Feed a high roughage diet and avoid changing the diet any more frequently than you have to. Keeping the diet consistent and forage-based will ensure a healthy and balanced population of bacteria in the hindgut.
  2. Speak to your veterinarian to develop a diagnostic-driven parasite management plan for your horses.
  3. Follow your veterinarian’s advice when using medications such as bute and flunixin and never change doses without first consulting your veterinarian.
  4. In areas where sand accumulation may be an issue (eg. WA and QLD), digital radiographs (Figure 1) can be performed to check for the presence of sand that can damage the hindgut.

horse gastric ulcers risks and signs

Figure 1. Sand accumulation in the ventral colon.

1. Pellegrini, FL 2005, ‘Results of a Large-Scale Necroscopic Study of Equine Colonic Ulcers’, Journal of Equine Veterinary Science, vol. 25, no. 3, pp. 113-117. 2. Kerbyson, NC, Knottenbelt, DC, Hotchkiss, J & Parkin, TDH 2017, ‘Idiopathic Colonic Ulceration: Prevalence, Gross Pathology and Clinical History in 56 Horses’, Equine Veterinary Journal, vol. 49, no. S51, pp. 13-16.


Written by Dr. Tania Sundra BSc.(Hons) BVMS MANZCVS (Equine Medicine)

Avon Ridge Equine Veterinary Services, Perth, Western Australia

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