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Service Information

  • Gastroscopy

    Equine Gastric Ulceration Syndrome (EGUS) is an important cause of poor performance in all types of horses.

    Signs of gastric ulceration are very varied. Classically we see a reduction in appetite, slowed eating and weight loss, however these are not present in all cases. Behavioural changes including resistance to girthing and being ‘grumpy ‘ are also common.

    Poor ridden performance is often the main reason for horses being presented for gastroscopy.  In these cases a wide range of problems are seen such as bucking, napping and refusal to jump.

    Gastroscopy is now common place in poor performance investigations.

    Gastroscopy can be performed in the clinic or out at your yard.

    To allow visualisation of the entire stomach it is essential that horses are starved for 16 hours prior to gastroscopy. Water should be withheld for 1 hour. We recommend the use of a muzzle for this. If starving is difficult for owners horses can be admitted to the clinic overnight prior to scoping.

    The horse is sedated and a 3.5M flexible endoscope is passed up the nose, though the pharynx, into the oesophagus and then advanced into the stomach.

    Once in the stomach both the fundus and the pyloric regions are examined. Ulcers are graded on a descriptive scale from 0 to 4.


    The horse’s stomach is required to be a very acidic environment to allow breakdown of their highly fibrous diet. Normally a careful balance exists between the acidic secretions and the protective mechanisms of the stomach. These include pH buffering saliva, a layer of skin-like cells in the upper stomach and a thick layer of mucous in the glandular portion. If this balance is altered, for example in times of stress or reduced food intake, then gastric ulceration occurs.

    There are two distinct anatomical areas of the stomach which develop different types of ulceration.


    These ulcers affect the top of the stomach and result from an increased exposure of the squamous mucosa to acid. They form quickly when acid splashing occurs as this portion of the stomach is less well protected.

    Trigger factors for this type of ulceration include forage deprivation, high starch diets, travel and intensive exercise.

    Medical treatment is with Omeprazole, which stops acid secretion. If used in alongside diet and management change it is usually very effective. Most lesions will heal within 2-3 weeks.


    The glandular part of the stomach makes up the bottom two thirds of the stomach. This area is responsible for secreting acid and other digestive enzymes. It is in constant contact with the acid. The glandular stomach is protected by a mucous layer. If this layer fails then this is when ulceration occurs. They will often develop more slowly.

    Additional factors include stress, bacterial infection and physical trauma.

    These ulcers are more often associated with poor performance as they are extremely painful. They usually are more difficult to treat and take significantly longer to heal.

    Medical treatment also involves Omeprazole. In addition, mucosal protectants such as sucralfate are often required. It is thought that bacteria may be associated with some glandular ulceration and antibiotics may also be used.


    • Try to ensure ad-lib access to good quality forage, ideally grass and hay.
    • Turnout as much as possible.
    • Ideally feed hay prior to hard feed.
    • Alfalfa has been shown in studies to be beneficial.
    • Feed a high level of oil in the diet.
    • Do not withhold feed prior to exercise.
    • Avoid cereal based feeds.

    Grade 3 ulceration

    Causes, treatment and prevention