Equine Grass Sickness (EGS) is a frequently fatal disease, affecting grazing horses, ponies and donkeys. However, there have been a few cases where equines with no access to grass have developed EGS and hay has been found to be the cause in those rare incidences.
A great deal of research has been put into EGS, much of it funded by the Equine Grass Sickness Fund. Currently, the precise cause of the disease remains unknown, but research continues to be a vital element in understanding this devastating disease.
EGS cases can occur at any time of the year but has been found to be most prevalent between April-June. The UK has the highest number of EGS cases compared to other countries in the world, with higher occurrences nearer the east coast compared to the west, particularly in Scotland. EGS can affect any age of horse but is most commonly seen in young adult horses between 2-7 years old.