Healthy digestion relies on balanced nutrition, continuous forage intake and a healthy digestive microbiome. This A-Z guide explains the key nutrients, digestive structures and nutritional concepts that support gut health and help maintain a healthy stomach from the inside out.
A – Acidity
The horse's stomach produces acid continuously, even when it is not eating. Regular forage intake helps naturally buffer stomach acid and reduces the risk of irritation to the sensitive upper stomach lining.
B – Buffering
Saliva produced during chewing acts as the horse's natural antacid. Fibre rich forage encourages prolonged chewing, increasing saliva production and helping neutralise stomach acid.
C – Caecum
The caecum is the horse's largest fermentation chamber, where billions of beneficial microbes digest fibre into volatile fatty acids (VFAs), an important source of energy.
D – Digestive Microbiome
The digestive microbiome is the community of beneficial bacteria, fungi and other microorganisms living within the gut. A balanced microbiome supports fibre digestion, nutrient absorption and immune health.
E – Equine Gastric Ulcer Syndrome (EGUS)
EGUS is the collective term for ulceration within the stomach. Good nutritional management plays an important role in reducing recognised risk factors.
F – Fibre
Fibre is the foundation of digestive health. Continuous forage intake supports normal gut function, encourages saliva production and helps protect the stomach lining from excess acid.
G – Gastric Mucosa
The stomach contains two different linings. The glandular mucosa produces protective mucus and bicarbonate, while the upper squamous region has little natural protection against stomach acid.
H – Hindgut
The hindgut, consisting of the caecum and colon, is where fibre fermentation takes place. Maintaining hindgut health is essential for efficient digestion and nutrient production.
I – Intestinal Integrity
A healthy intestinal lining supports efficient nutrient absorption while acting as a protective barrier between the digestive tract and the bloodstream.
J – Jejunum
The jejunum is the middle section of the small intestine where much of the digestion and absorption of amino acids, fats, vitamins and minerals occurs.
L – Lucerne (Alfalfa)
Lucerne is naturally high in calcium and quality protein, helping buffer stomach acid and supporting a healthy stomach environment when fed appropriately.
M – Mucus Barrier
The glandular stomach produces mucus and bicarbonate, creating a protective barrier that shields the stomach lining from acid.
N – Nutrition
Balanced nutrition provides the fibre, protein, vitamins and minerals required to maintain healthy digestive tissues and support normal gut function.
O – Oligosaccharides (Prebiotics)
Certain oligosaccharides act as prebiotics, providing nourishment for beneficial gut bacteria and helping maintain a balanced digestive microbiome.
P – Prebiotics & Probiotics
Prebiotics feed beneficial gut microbes, while probiotics provide live microorganisms that may help support microbial balance during periods of stress or dietary change. Saccharomyces cerevisiae is the probiotic to look out for, this has been authorised by the EU for equine consumption as a digestability enhancer.
Q – Quality Forage
Good quality, clean forage provides the fibre required to support digestive health, microbial fermentation and consistent gut function.
R – Roughage
Long-stem roughage forms a fibrous mat within the stomach, helping reduce acid splash while supporting normal digestive physiology.
S – Starch
Excessive starch intake can increase ulcer risk and disrupt hindgut microbial balance if undigested starch reaches the large intestine.
Ideally, starch is digested in the small intestine, where enzymes break it down into glucose for absorption. However, when a horse consumes large starch meals, some starch can escape digestion and pass into the hindgut.
There, rapid fermentation by starch loving bacteria can:
- Lower hindgut pH (hindgut acidosis)
- Disrupt the balance of beneficial microbes
- Increase the risk of digestive disturbances
- Contribute to poor gut health and, in some horses, increase the risk of conditions such as gastric ulcers, colic and laminitis.
T – Trace Minerals
Trace minerals including zinc, copper and manganese support tissue maintenance, immune function and normal repair of the digestive lining.
U – Ulcers
Gastric ulcers occur when stomach acid damages the stomach lining faster than protective mechanisms can repair it. Nutritional management is an important part of supporting stomach health alongside appropriate veterinary treatment.
V – Volatile Fatty Acids (VFAs)
VFAs are produced when hindgut microbes ferment fibre. They provide a major source of energy for the horse and support overall digestive health.
W – Water
Fresh, clean water is essential for digestion, fibre fermentation, gut motility and nutrient absorption.
Y – Yeast
Live yeast supplements may help support fibre-digesting bacteria, promoting hindgut stability and digestive efficiency.
Z – Zinc
Zinc supports normal tissue maintenance, immune function and repair of the gastrointestinal lining.
Key Takeaway: Gut Health Begins With Nutrition
The horse's digestive system is designed to process small amounts of fibre almost continuously throughout the day.
Healthy digestion depends on:
- Continuous access to fibre and forage
- Natural buffering of stomach acid through chewing and saliva
- A balanced digestive microbiome
- Controlled starch intake
- High quality forage
- Adequate water intake
- Balanced vitamins and trace minerals
When these nutritional factors work together, they help maintain a healthy stomach environment, support hindgut fermentation and promote long term digestive health.
Understanding how nutrition influences every stage of digestion is the foundation of healthy gut function and reducing the risk of gastric ulcers.