The disease can affect any breed...

Dubai Millennium's untimely death in 2001 shocked the racing world. Sheikh Mohammed's beloved entire was only five years old when he lost his battle with grass sickness, proving that even the most well cared for equines can succumb to the disease. Cases of grass sickness peak in the spring and so we at the-racehorse.co.uk spoke to the Equine Grass Sickness Fund to find out more about this devastating disease...

What are the signs of grass sickness?

The disease, which is manifest by impaired activity of the gut due to damage to the autonomic nervous system, occurs in three overlapping forms - acute, subacute and chronic. In acute cases, the signs come on suddenly and are severe. They include - colic, reflux of green stomach fluid down the nose, difficulty in swallowing, muscle tremors, abnormal sweating patterns, impaired gut activity and impaction of the colon. Sadly, acute cases cannot be treated and euthanasia is the only option.

...as fans of Dubai Millennium know

Trevor Jones 2006

In subacute cases, the signs are milder than those listed above and some subacute cases do progress to the chronic form. In chronic cases (where the equine is still alive eight or more days from the onset of the disease) the signs are more gradual and include marked weight loss, variable difficulty in swallowing and abdominal discomfort, muscle tremors, sweating, slow gut activity and a "snuffling" sound during breathing, due to blockage of the nasal passages with mucus. This form of the disease can be treated successfully in some cases. (excerpt from 'Management of Chronic Grass Sickness Patients' by Dr E Milne).

What causes grass sickness?

The causes of the disease are not clear at present, but recent research strongly implicates involvement of the soil borne bacterium Clostridium botulinum. Development of a vaccine is currently underway in the USA, but it may be several years before it becomes available.

Grass sickness occurs in most parts of the UK mainland, mainly in grazing horses aged between two and seven. The vast majority of cases occur during the spring and summer with a peak incidence in May.

The disease can affect horses, ponies and donkeys, and as the new grazing season approaches, owners must be vigilant in observing any changes to their equine's normal eating/drinking habits or behaviour.

The Equine Grass Sickness Fund (EGSF) based near Edinburgh is the only registered charity that raises funds specifically for research into grass sickness. For the past 18 years, it has funded many research projects aimed at finding the cause of the disease and offers advice and support to owners of affected animals. Donations towards research are always welcome. If you have a grass sickness case please report it to the EGSF by using the case form on their website at www.grasssickness.org.uk or by contacting them on 0131 445 6257.