Keep Horses Away from Sycamore Trees to Prevent AM

Keep Horses Away from Sycamore Trees to Prevent AM

Heath, the rehomed Blue Cross pony, who died from atypical myopathy last week.

Photo: Courtesy Blue Cross

Blue Cross, a U.K.-based animal welfare charity, is urging to keep their horses away from sycamore trees following the death of one of the charity’s rehomed ponies caused by atypical myopathy (AM). The charity, in conjunction with veterinarians, has put together some tips to help keep horses safe.

Atypical myopathy is a highly fatal muscle disease often seen in horses in the U.K. and Northern Europe. Researchers believe AM is caused by the ingestion of hypoglycin A, a toxin found in sycamore tree (Acer pseudoplatanus) seeds. Researchers have linked a similar condition found in horses in the United States, referred to as seasonal pasture myopathy (or SPM), to hypoglycin A toxins from box elder tree (A. negundo) seeds.

British veterinarians have seen a rise in new cases of AM this spring. Young horses appear to be more susceptible, as are those being grazed on parched land, they observed.

“Horse owners need to be alert at all times but especially during the spring and autumn months," said Blue Cross veterinarian Natasha Seely, BVM&S, MRCVS, of Bourton Vale Equine Clinic in Gloucestershire, England. "If they are worried that their horse may be showing and symptoms they must call their vet immediately. The signs range from depression, muscle weakness, recumbency, choke, or colic-like symptoms to dark red urine. The sooner AM is diagnosed the better the likely outcome.”

The Blue Cross and veterinarians at Bourton Vale Equine Clinic recommend owners follow some tips to help protect horses from contracting AM:

  • If your fields are parched or grazed down, feed hay in a net or feed rack rather than off the ground;
  • Do not over stock pastures;
  • Stable horses at night;
  • If you aren't able to remove horses from pastures with potentially dangerous trees, fence off areas around the poisonous plants, and collect and dispose of leaves safely away from horses;
  • Remove young sapling plants before they grow;
  • Limit horses' access to streams running through paddocks, as researchers believe AM could be more prevalent in moist places;
  • Watch for potential signs of disease and act quickly if your horse is showing signs of illness;
  • Check your horse regularly, at least twice daily, to be sure he's in good health; and
  • If applicable, ensure your horse's insurance is up-to-date.

Gemma Taylor, education officer at Blue Cross, continued, “One of our horses in an experienced loan home unfortunately lost his battle with this fatal disease last week. Although his field did not have any sycamore trees nearby it is thought that he had ingested seeds brought in by floodwater. This … incident has bought it home how horrific this disease can be and how all horse owners have to stay alert to the dangers to try to minimize this dreadful disease.”

Stay on top of the most recent Horse Health news with FREE weekly newsletters from Learn More