Equine grass sickness

Equine grass sickness (EGS) is a debilitating and often fatal disease which commonly presents as impaired activity of the gut, caused by nervous system damage, which prevents food from travelling through the digestive system properly.

Cases are common in northern European countries, particularly Great Britain. The disease occurs almost exclusively in horses with access to grass, but even though the condition was first identified around 1909, the true cause of EGS remains unknown.

The disease can present as acute (sudden onset), subacute (milder clinical signs) and chronic (slow onset).

Acute and subacute clinical signs include, but are not limited to:

Absence of gut sounds
Increased heart rate
Gastric reflux (food out of nostrils)
Colic
Difficulty swallowing

Clinical signs in chronic cases can include:

Rapid otherwise unexplained weight loss
Tucked up abdomen
Drooping eyelids
Muscle tremors.

Contact your vet immediately if you suspect your horse is displaying signs of grass sickness.

Fast Facts guide to Equine grass sickness

The front cover of the Fast Facts Equine grass sickness guide showing a chestnut horse grazing in a field surrounded by trees.

This Fast Facts guide includes:

Clinical signs of the different types of grass sickness
Treatment of grass sickness
Risk factors and prevention strategies

Download PDF

How do you manage chronic equine grass sickness?

The cause EGS is still unclear, but some horses survive with intensive nursing. Thanks to the dedicated team at the University of Edinburgh and with World Horse Welfare’s support, the following guide on the management of horses with chronic grass sickness was produced.

Management of horses with chronic grass sickness

Management of chronic grass sickness horses

This guide focuses on:

The clinical signs of chronic EGS
Diagnosis and treatment of chronic EGS
Prognosis and recovery of horses with chronic EGS

Download PDF

Further updates on EGS research can be found in the guide below: