Page 511 - The Veterinary Care of the Horse

• more serious complications include choke and inhalation pneumonia

VetBooks.ir Prevention

Vaccination against EGS may be possible in the future. In 2014 the Animal Health Trust
began a vaccine trial involving 1,100 horses and ponies in areas affected by EGS. Half of the

animals were given the Clostridium botulinum Type C vaccine and the other half an inactive
placebo injection. The type of injection was randomly assigned and neither the owner nor

their vet knew which the individual horse had received. Three injections were administered at
3-week intervals and a booster was given a year later.

A pilot field trial of the vaccine showed it to be safe and to stimulate a significant
increase in antibody levels. At the time of writing, a much larger nationwide vaccine trial is

being undertaken.

Other preventive measures include:

• Stabling the horse all the time or avoiding the use of fields where the disease has
occurred, especially in the spring and summer.

• If this is not practical or possible, horses should be offered hay or haylage in the field
during the high-risk period.

• Stable horses in affected areas following a 7–10 day period with temperatures of between
7–11 °C.

• Mixed grazing with cattle or sheep may reduce the risk.

• Stable horses moving onto high-risk premises for the first 2 months.

• Remove droppings from the pasture by hand.

• Minimize stress of horses kept in high-risk areas.
• There may be an association between frequent use of certain anthelmintics and grass

sickness in susceptible horses; however, more work needs to be done on this; check with
your vet for current advice. Avoid overuse of anthelmintics.

ATYPICAL MYOPATHY

Atypical myopathy, also known as seasonal pasture myopathy, is caused by the ingestion of a

toxin hypoglycin A, contained in the leaves, seeds and seedlings of the sycamore tree Acer
pseudoplantus in Europe and the box elder (Acer negundo) in the United States. Some North
American and Japanese acers (or maples) that are grown as garden trees and shrubs can also