Atypical Myopathy – what you need to know

With Autumn in full swing, the risk of Atypical Myopathy heightens. So we provide a quick guide as to what to look out for and how it can be avoided as part of a land management schedule.

What is Atypical Myopathy?

Atypical Myopathy is more commonly known as Sycamore poisoning. It is caused when a horse easts Sycamore seeds, and sadly it can be fatal. The disease is more common in the autumn, and often occurs when large numbers of seeds are falling.

What causes atypical myopathy?

A toxin (Hypoglycin A) is found within the seeds and seedlings of a sycamore which prevents energy being produced within muscle cells causing the muscle cells to die. The amount of toxin within seeds and seedlings is variable and susceptibility varies from horse to horse.

Mild weather conditions are also linked to outbreaks of atypical myopathy, which is thought to affect the concentration of toxin in the seeds and the mild spring, summer and autumn we have had this year may go a long way to explaining the large increase in cases seen in practically all areas of the UK.

Younger horses appear to be more susceptible, as are those being grazed on parched land.

What are the signs of Atypical Myopathy?

Horses with Atypical Myopathy may present a range of symptoms, but typically become very dull, weak, stiff and trembly. The first signs are often lethargy, a quiet demeanor or reluctance to work.

Other symptoms include:

  • Sweating
  •  Depression
  • Difficulty breathing
  • Red or brown urine
  • Choke
  • Colic
  • Low head carriage
  • Fast or irregular heart beat

If you suspect your horse showing any of the signs or symptoms, call a vet without delay.

How can I prevent atypical myopathy in my horses?

Prevention is better than cure. So it’s best to check for the presence of sycamores around your fields. Keeping horses a safe distance from sycamore trees can greatly reduce the likeliness of them suffering.

If you do have Sycamores within the vincity of your paddocks there are a number of steps you can take:

• Regularly check for when seeds are falling

• Fence off areas where sycamore seeds are likely to fall

• Only turn horses out for a few hours each day and keep younger horses furthest away from the sycamores and Provide additional forage especially where pasture is poor or grazing is tightas it makes it less likely that horses will be interested in eating the seeds.

• Reducing the number of horses in a paddock or field lessens the pressure on the land meaning grazing is of better quality, again so horses are less interested in eating seeds.

Photo taken by Mackenzie Taylor

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