Let us start with the basics: what exactly is the gut microbiome? It is billions of microorganisms, mainly bacteria, living in the horse’s intestines. They are responsible for breaking down the crude fibre from forage, for producing B vitamins and vitamin K, and for producing the volatile fatty acids that are a source of energy for the horse. The role of the microbiome does not end with digestion, however. The gut is the horse’s largest immune organ. It is there that immunity is shaped, and the microbiome is a key part of it.
Why, then, are disturbances of the microbiome so dangerous? Dysbiosis, that is a loss of balance in the gut microflora, leads to many health problems. Starting with colic and diarrhoea, through ulcers, and on to a drop in immunity, chronic inflammation and a deterioration in the quality of the hooves and coat. The microbiome even affects the horse’s behaviour, because the gut produces neurotransmitters that regulate mood and the level of stress.
What disturbs the gut microbiome in horses? Above all, feeding mistakes, such as too much cereal in the diet, sudden changes of feed, poor-quality feeds with mould or mycotoxins, and limited access to forage. Transport stress, competitions, antibiotic treatment and worming also affect the balance of the microflora.
So how can you support your horse’s gut microbiome every day?
✅ The foundation is constant access to forage, ideally good-quality hay. The horse needs a constant supply of fibre to keep the balance of the gut bacteria.
✅ Limit the share of cereals in the diet. If the horse needs extra energy, consider high-fibre feeds, vegetable oils or sugar beet pulp without molasses.
✅ Avoid sudden changes in feeding. Introduce every new feed slowly, over about 7-10 days.
✅ Consider using probiotics and prebiotics, especially in periods of stress or illness, or after antibiotic treatment.
✅ Give the horse daily exercise and limit stress: both improve gut motility and the functioning of the microbiota.
✅ Keep worming regular and base it on faecal tests, because parasite burdens have a negative effect on the microbiome.
To sum up, if you want your horse to have strong immunity, plenty of energy for work and healthy hooves, look after its gut first of all. The gut microflora is the foundation of health, and whether it functions properly depends above all on the right feeding and on keeping stress to a minimum. If there are digestive problems, it is always worth discussing the diet with an equine nutritionist and talking through probiotic supplementation with your vet. Remember: a healthy microbiome means a healthy horse!