Farmers are being warned of the potential risk of poisoning that common sycamore (Acer pseudolatanus) seeds and seedlings have on horses after a bumper crop of sycamore seeds last autumn.
The common sycamore seed contains a toxin called Hypoglycin A, which remains at high concentrations in seedlings and saplings. Their consumption can potentially be fatal to horses, resulting in muscle damage, a condition called atypical myopathy. Despite severe equine sensitivity, evidence suggests that ruminants possess a resistance to the toxin.
The British Equine Veterinary Association (BEVA), representing horse vets across the UK, is therefore warning farmers of the additional dangers this year of cutting hay from pastures contaminated with sycamore seedlings and saplings.
While there are herbicides available on the market for targeted use on these saplings, research shows that the plant retains the toxin after wilting. Physical removal of seeds and plant growth from grassland or if practical fencing off areas with high densities of seedling growth is advised as good practice, and farmers are being asked to bear such risks in mind given the particular risks that winter feed contaminated with sycamore growth can have on horses, especially now, when closing off hay fields intended for equine consumption.