This week, we are looking at the importance of being able to recognise the symptoms of Equine Gastric Ulcer Syndrome and how you can use feeding and diet to help prevent the onset of this increasingly prevalent disease, which is affecting more horses now than ever before as a result of changing modern feeding practices, environment and workload.
What is Equine Gastric Ulcer Syndrome?
Equine Gastric Ulcer Syndrome (EGUS) describes the erosion of the horse’s stomach lining as a result of prolonged exposure to gastric acid, and is the hidden health threat affecting horses and ponies of all ages, becoming an increasingly common risk to equine health.
Gastric Ulcers differ in severity and are graded on a scale between 0 – 4 and occur when factors in gastric juice, such as acid and digestive enzymes, overpower the protective factors in the stomach lining:
There are two types of gastric ulcers which occur in horses as the stomach is divided into two distinct regions:
This type of ulceration occurs in the dorsal region of the stomach which is lined with squamous epithelium cells and is very sensitive to the direct results of extended exposure to acid secretions, as no protective factors such as mucus and bicarbonate are produced there. Most ulceration tends to occur at the base of the oesophagus which lies in this region.
The ventral region of the stomach is lined with glandular epithelium cells which secrete the gastric acid that causes the ulceration of the lining. However, this region also secretes mucus and bicarbonate which protect the sensitive mucosa lining and reduce the incidence of ulceration, unless the area is previously compromised as a result of the use of nonsteroidal anti-inflammatory drugs such as Bute, which can decrease mucus production over time
Which horses are at risk?
It is now believed that any horse or pony of any ages could be at risk of developing gastric ulcers; however, there are certain groups which are particularly susceptible. Racehorses have the highest incidence of Equine Gastric Ulcer Syndrome and are most at risk due to the high level of concentrates in their diets and also, their increased levels of exercise. In addition, even foals are at risk of developing ulcers as they secrete highly acidic gastric fluids from as early as two days of age which are very damaging to their extremely sensitive, developing stomach lining.
Performance horses are also at risk due to their increased workload, feed and the levels of travelling they have to endure, contributing to elevated stress levels, and as a result, it is believed that this can lead to the development of ulcers.
What are the risk factors of Equine Gastric Ulcer Syndrome?
There are several risk factors that contribute to the development of an ulcer, the most common being diet and feeding regime, exercise, stress and medication. It is important to note that horses can develop ulcers in the absence of these characteristic contributing factors:
Diet and Feeding Regime
Horses in their natural environment are designed to ‘trickle feed’ and spend around 16 hours per day grazing. In this state, the stomach produces a constant flow of acid which is buffered by the saliva produced in response to constant grazing. However, modern practices where it is common to feed twice a day, have caused an alteration to this natural pattern of feeding, whereby the reduction in forage and increase in concentrated feed has led to horses being fed less frequently. This prolongs the period where the increased levels of stomach acid is not being neutralised by the effects of saliva and mucus production stimulated by feeding
Exercise has been linked to Equine Gastric Ulcer Syndrome as it increases gastric acid production, which then as a result of movement, is splashed up into the squamous portion of the stomach, exposing it to an acidic pH. Also exercise decreases blood flow to the GI tract which is important in removing stomach acid, whilst the increased pressure in the abdomen pushes acid up to the sensitive portion of the stomach.
Gastric ulcers can occur in response to mental and physiological stresses such as shock, traumatic injury, travelling, competing, training and stable confinement. When horses are subject to long periods of travel, they experience intermittent feeding and stress which leads to gastric acid build up and therefore damage to the stomach lining.
Chronic administration of nonsteroidal anti-inflammatory drugs such as phenylbutazone (‘bute’) can decrease the production of the stomachs’ protective mucus layer, increasing risk of developing an ulcer
What are the clinical signs?
The signs of gastric ulcers can be difficult to recognise and a large proportion of horses do not show outward clinical signs but instead display the following more subtle indicators of their condition:
- Poor appetite
- Attitude changes
- Decreased performance
- Poor condition and dull coat
- Weight loss
- Excessive resting, lying down and yawning
- Behavioural changes
- Mild or recurrent colic
More severe cases exhibit teeth grinding, excess salivation and prolonged periods of recumbence, especially in foals who are commonly found to lie on their backs as this position provides relief from the pain of ulceration. Some horses never show any signs, but still have been found to have ulcers.
How is Equine Gastric Ulcer Syndrome diagnosed?
The most definitive diagnosis of Equine Gastric Ulcer Syndrome is via a gastric endoscopy or gastroscopy, which involves the insertion of a camera into the stomach to assess the condition of the squamous and glandular epithelial linings as well as the proximal segment of the small intestine. It was not until the middle of the 1980’s that an endoscope was developed that could look into the horses’ stomach, making diagnosis much more accurate.
Clinical factors will be carefully assessed prior to a scope and horses are usually fasted for a period of twelve hours prior to the procedure so a complete evaluation can take place
As with most conditions, Equine Gastric Ulcer Syndrome is better to be prevented rather than treated and there are several risk factors that can be effectively minimised by sensible approaches to feeding and management
- Include as much forage or natural grazing in the diet as possible. A high level of forage and regular trickle feeding will increase saliva and mucous production, buffering the effects of constantly produced gastric acid and encourage efficient passage of food through the digestive tract, keeping it healthy and at a lower risk of disease
- Increase the time in which feed is consumed. For a stable kept horse, use small holed haynets to maximise the period of time it takes to consume the forage, reducing the period of time that the horse is without food
- Use low starch and sugar feeds, and a Blue Chip Balancer to reduce hyperactivity and stress and therefore allow efficient transit through the GI tract as stress and digestion are symbiotically linked.
- Include a probiotic in your horses’ diet. All the Blue Chip balancers incorporate the highest quality, EU approved probiotic in their formulation to restore the balance of ‘healthy’ bacteria in the gut to improve nutrient absorption and digestion
- Reduce the amount of time stabled. Ensure that your horse is accompanied by other horses to increase socialisation and reduce stress and anxiety
- Only use nonsteroidal anti-inflammatory drugs when absolutely necessary to minimize the risk of damage to the glandular epithelium