Grass sickness was first diagnosed in Eastern Scotland in 1909 but still a “mysterious” disease.
Thought to be related to Clostridia bacteria but also suspicion about clover species.
Colic signs of some horses that have access to pasture.
It is a disease of the Autonomic Nervous System i.e. the part of the nervous system that carries out subconscious or “automatic” actions such as gut movement, breathing etc.
Acute- Sudden onset
Sub-Acute- slightly longer in onset
Chronic- longer term but less severe signs
Colic, lack of gut sounds, not eating, high heart rate, muscle twitching/tremors, irregular patchy sweating, drooping eye-lids (ptosis),
- Sub Acute
Slightly less severe clinical signs as acute
Weight loss, tucked-up (greyhound-like) appearance of abdomen, not eating, dry & inflamed nasal passages (rhinitis sicca)
- Ileal biopsy
Biopsy of the lymph nodes (“glands”) from the area of the small intestine known as the ileum, This is the only definitive disease
- Phenylephrine eye drops
This reduces the drooping eyelids that can be seen with this disease
- No treatment for this disease. Euthanasia is the best option.
- Sub-Acute. Realistically euthanasia is the best option.
- These can be nursed back to a reasonably normal life although they tend to be “poor doers”. This takes huge commitment and a lot of effort by everyone.
- Areas or regions of the country (Scotland)
- Specific farms (where previous history of cases)
- Age of horses (peak is 3-4 years of age)
- Time of year- peak late summer (May) and smaller peak in Autumn
- Horses turned out day and night
- Soil types (high nitrogen content)
- Harrowing or automatic poo pickers (soil disturbance)
- Weather (2 weeks of cool & dry weather)
- New arrivals on a yard
- Stress- travelling, castration, breaking, new arrivals to herd
- Body condition- good to fat
Good pasture management
Manual poo-picking (NOT automatic poo-pickers)
Ensure adequate grass or provide additional hay/haylage
Co-graze with cattle/sheep
Good horse health
Good gut health
Avoid over use of ivermectin wormers
Vaccination trials have been done recently at the Animal Health Trust with the aim to produce a commercial vaccine.
The future will hopefully yield a vaccine against Clostridia bacteria which should prevent or help to prevent Grass Sickness.