Dozens of Horses Die in Switzerland Following Sycamore Seed Poisoning Wave

At least 26 horses have died across the cantons of Jura and Bernese Jura following an outbreak of atypical myopathy, a severe and frequently fatal poisoning caused by the ingestion of sycamore maple seeds. Local horse breeders and veterinary experts have urged owners to remove their animals from pastures immediately to prevent further exposure to the plant toxin.

Mario Gandolfo, a breeder from Fregiécourt who initiated a monitoring group with fellow livestock owners, confirmed the mortality figures in an interview with Western Swiss broadcaster RTS. Gandolfo reported that 26 horses had died in the Jura and Bernese Jura regions, while 14 others were receiving treatment in animal hospitals. He added that additional fatal cases occurred in the cantons of Fribourg and Lucerne. In Cortébert, breeder Audrey Steulet-Geiser lost 10 horses from her 36-head herd, with the remaining animals transported to clinics for medical care.

Veterinarian Stéphane Montavon stated that symptoms develop rapidly, typically presenting between 12 and 24 hours after toxin ingestion. The first observable sign is dark urine, often tea- or cola-colored, followed by severe muscle weakness, stiffness, tremors, elevated heart rates, and respiratory distress. Montavon noted that the condition carries a mortality rate of between 75 and 90 percent.

Environmental conditions contributed to the high number of poisonings this autumn. Prolonged dry weather and a shortage of alternative feed led farmers to leave herds on pasture longer than usual, while recent strong winds distributed large quantities of winged sycamore seeds across grazing areas. Because atypical myopathy is classified as a non-contagious poisoning rather than an infectious disease, cantonal animal epidemic funds do not compensate breeders for financial losses associated with dead stock.

Written by Andreas Hofer andreas.hofer@alpineweekly.com