CULTURE MOMENT: ulcers

The horse is a monogastric herbivorous animal, with a complex and sensitive digestive system: a single very small stomach and a long, narrow small intestine. These peculiarities can be explained by the fact that before they were domesticated by humans, horses in the wild fed on forage in small quantities throughout the day. It is therefore necessary to understand the horse’s digestive system in order to adapt its diet and activity.

Digestion begins in the mouth: chewing in horses is quite long, allowing the feed to be ground and the food bolus to be moistened. Unlike cattle, the bolus will not be chewed a second time, so the chewing phase stimulated by the secretion of saliva in the horse is important for good digestion. The drier and larger the food, the longer the chewing will take: the insalivation of the food bolus allows the digestion of starch to begin and neutralizes the acidic pH of the stomach. Permanent access to clean water for a horse is therefore essential.

After swallowing, the food passes through the esophagus, a narrow canal of about 1.2m to 1.5m, and descends to the stomach through a system of contractions throughout the esophagus. The horse’s stomach is small compared to other ruminants: only 8% of its digestive tract. The stomach fills up to 2/3 maximum, so the splitting of feed rations in horses is essential. It begins with the cardia, a very tight sphincter preventing any food from rising into the esophagus (vomiting) and ends with a pylorus. Two mucous membranes line the walls of the stomach: on the upper part, it is the squamous mucosa lacking a protective barrier and glands secreting gastric juices (the pH of this area varies from 5 to 7), and the glandular mucosa in the lower part where the pH is therefore very acidic between 1 and 2. This mucous membrane is protected from acidity by its mucus, keratin and bicarbonates. The stomach empties gradually, the larger the meal and richer in starch, the less rapid the gastric emptying.

Once the bolus is predigested, it then arrives in the small intestine, divided into 3 parts: duodenum, jejunum, ileum. It represents 30% of the horse’s digestive system: from 20 to 22m. The digestion of proteins, lipids and carbohydrates really begins in the small intestine thanks to the action of pancreatic juices, intestinal enzymes and bile. The walls of the small intestine also show villi that allow the absorption of digestion products by the body. In about 3 hours, the bolus passes through the intestine, this time increases if the meal is large or too rich in starch, to then arrive in the large intestine. The latter represents 60% of the digestive tract, food passes through it in 24-48 hours. Thanks to the action of the microbiota, the fibres, residual proteins and starch are degraded, and the last elements present are absorbed, including water, thus allowing the formation of droppings.

WHAT ARE ULCERS ?

Unlike the human stomach, a horse’s stomach continuously produces stomach acid: 10 to 30L per day, because a horse is designed to eat small amounts throughout the day. Anatomically, the walls of the horse’s stomach are covered with a mucous membrane: a scaly mucosa in the upper part and a glandular mucosa in the lower part. The latter, which is in contact with stomach acid, contains glands that provide a protective barrier of mucus and keratin to neutralize stomach acid. The wall of the upper part of the stomach is devoid of these glands because it is not supposed to have a pH below 4.

Due to the horse’s gastric sensitivity, ulcers are very frequently encountered, it is one of the most common digestive diseases in horses. The ulcer corresponds to a more or less significant erosion of the mucous membrane that lines the walls of the stomach.

Ulcers of the squamous mucosa (upper part) are observed when the walls of this part are confronted with a pH that is too acidic, a pH below 4, or when a high acidity is present for a long time in the stomach.

However, an ulcer of the glandular mucosa, which is normally protected from stomach acid, can be diagnosed. This is thought to be the result of an imbalance between acidity and these barriers, or a weak immune system. The causes of these ulcers have not yet been clearly identified.

The majority of ulcers in horses are observed at the level of the margo-plicatus, the boundary between these two mucous membranes.

Some risk factors have been highlighted, such as:

• Intense exercise
• An unsuitable diet (prolonged diet, too rich in cereals, etc.)
• Stress
• Prolonged anti-inflammatory treatment
• Certain diseases

SYMPTOMS

The symptoms of a gastric ulcer are variable and non-specific. The main signs we may encounter are:

• A general decrease in shape: dull hair, pitted hair, capricious appetite, weight loss, muscle weakness, repeated yawning
• A change in behaviour: fatigue, nervousness, reluctance to exert effort, skin sensitivity
• Colic after meals
• Hypersalivation
• Teeth grinding called “Bruxism” related to stomach pain
• Repetitive movements: tics in support, tics in the air…

These clinical signs are non-specific, they can be severe or benign, and are not often indicative of the severity of the ulcer: small symptoms can hide a large ulcer. It is therefore essential to be accompanied by a veterinarian in order to establish a diagnosis.

Vigilance is required for young horses, ulcers can worsen very quickly. At a very advanced stage, the erosions are very deep in the mucous membrane until they reach the blood vessels and cause blood to flow into the stomach. Digested blood can thus be observed in the droppings.

WHAT TO DO

When the slightest doubt arises, the reflex is to consult a veterinarian to carry out a clinical examination and to know the location of the ulcer and its severity. Your veterinarian will advise you as best as possible for the drug treatment to be carried out and with regular veterinary follow-up throughout the treatment.

At the same time, it will be necessary to identify the causes of this ulcer and consequently modify the diet, activity, rhythm of life, environment, etc. There are many causes that can cause this pathology: undivided rations, insufficient forage intake, excessive starch intake. Many horses do not have continuous access to roughage and therefore have to fast while their acid production in the stomach continues, the stomach wall can be damaged. Similarly, it is preferable that the horse’s stomach is filled before any physical exercise, and to avoid situations that are too stressful.

When the veterinary treatment is over, we recommend administering our STOP’ ULCE in order to consolidate and strengthen the stomach walls damaged during the ulcer. Our complementary food coupled with good feed management will strengthen the mucous membranes of the stomach to prevent recurrences. You will find all the information: https://naturacheval.fr/produit/stop-ulceres-liquide/