The Stables

A Typical Worry

Summer seems to have skipped by and autumn is knocking on the stable door. The flies will soon disappear, the rugs will be soon dusted off and the clippers will need oiling….

However much we prepare for the cooling months in horse ownership, there is always some worry or two that changing seasons brings. Over the last few years there has been an alarming rise in horses simply dying from a disease that is difficult to control if your grazing is near woodland… and particularly sycamore trees.

Atypical Myopathy is caused by horses that eat sycamore leaves and seeds which contain toxin and poisons. Hundreds of horses are dying every year from this humble helicopter leaf that is falling from the trees, travelling in the air for some distance before resting deadly in grazing paddocks. It is believed that at least four hundred horses died alone of this disease last autumn.


Some of the symptoms can be subtle to start with and can easily be put to other conditions, ie you have an aging horse that is stiff or weather conditions may be too hot or dry. However, if these early warning signs persist then call your vet as soon as you can to eliminate this horrible and shocking disease. Without treating the disease results in muscle damage and particularly affect the muscles that enable the horse to stand, the muscles that allow breathing and the heart muscle. As a result, horses can display a range of signs but typically become very dull, weak, tremble, show signs of pain may be unable to lift their heads or even remain standing. Here are the symptoms you should look out for:-


  • Muscle soreness
  • Stiffness
  • Muscle tremors
  • Weakness
  • Lethargy
  • Fast or laboured breathing
  • Reluctance to work
  • Red or brown urine
  • Choke
  • Whinnying
  • Head tossing or low head carriage
  • Fast or irregular heart beat
  • Sudden death

 Currently, there is no cure for the illness, which strikes suddenly ad causes distressing death within hours. Sadly the statistics are high with seventy-eight percent of horses that contract atypical myopathy will die. If the illness is caught early enough, vets can offer treatment such as putting the horse on a drip to flush out the toxins before the poison travels too far into their system. Other treatments include anti-inflammatories, glucose and vitamin C. However if not treated in time, the illness can cause sudden muscle collapse leading to the inability to breath and finally it can cause heart failure which is most cases is fatal.



It is incredibly difficult to monitor leaves that fall in paddocks. If your grazing is directly lined with sycamore trees, then through the autumn months horses should be removed from this pasture. However, these leaves can travel for miles in the wind and then land unsuspectedly on to the ground, without us knowing. Sectioning off paddocks near trees with small areas of grazing is easier to check the pasture, especially when poo picking.


If you see sycamore saplings coming up in your pasture, remove them. If the grazing is poor, then supplement with hay or haylage so the horse stops foraging on the ground for food. Make sure your horse is up to date with their vaccinations as it has been proven that unvaccinated horses are more at risk of developing the illness. Listen out for cases in your area, if there have been some in the past then limit your horse’s turnout through these risky months and be vigilant for the leaves and signs of the illness in your horse.


If you have any doubts about subtle first symptoms in your horse, call your vet immediately. It is always better to be safe rather than very sorry.


Written by Samantha Hobden

Image Source: Pixabay