Be prepared before Seasonal Pasture Myopathy strikes, advises BEVA

With Autumn round the corner and trees clearly displaying their seeds now is the time to identify and deal with the risks of any sycamore trees on or near your horse’s grazing advise vets at the British Equine Veterinary Association (BEVA). Sycamore seeds are toxic and can cause the fatal disease Seasonal Pasture Myopathy (SPM) (also referred to as Atypical Myopathy).

Seasonal Pasture Myopathy is a highly fatal muscle disease in horses caused by the toxin hypoglycin A, which is contained in tree seeds including that of the sycamore. While sycamore seeds may not be directly palatable to horses, those grazing on poor quality pasture may ingest considerable numbers of them. Horses kept in sparse pastures with an accumulation of dead sycamore leaves, dead wood and trees in or around the pasture and without access to supplementary hay or feed, are the most susceptible.

Horse owners are advised to identify sycamore trees on or near grazing land and take steps before the autumn to prevent the seeds falling where they are in reach of horses.

• Ideally move horses off pasture at times of risk.
• Restrict access to seeds by using temporary fencing.
• Ensure horses have access to good quality uncontaminated pasture.
• Provide consistent access to clean, palatable hay or haylage to minimise the risk of horses being tempted to ingest seeds.
• Do not fell trees, since doing so can lead to massive pasture contamination, further increasing the risks to horses
• Discuss the risks and how to identify early clinical signs of SPM with your veterinary surgeon.
• Be aware that a field without sycamore trees can still contain seeds spread by high winds or flood water.

Mark Bowen, Senior Vice President of BEVA said: “Please plan ahead and take steps now to prevent the risk of your horse contracting Seasonal Pasture Myopathy. It’s a devastating condition that can frequently be fatal despite treatment. If you are worried about the safety of your grazing speak to your veterinary practice for advice.”