Toxic maple seeds kill 26 horses in Jura and Bernese Jura

At least 26 horses have died and 14 more are being treated in clinics after being poisoned by sycamore maple seeds in the Jura and Bernese Jura, SRF reported. Drought has kept herds on pasture longer, while strong winds have spread the seeds widely.

The seeds contain a toxin that causes atypical myopathy, also known as pasture myopathy, a frequently fatal disease affecting horses and related species. Mario Gandolfo, a breeder in Fregiécourt in the canton of Jura, told French-language broadcaster RTS that he also knew of three cases elsewhere: one in Fribourg and two in Lucerne, all fatal.

Gandolfo and other breeders have started a group to track cases and deaths and warn owners. He urged people to move their horses off pasture and into stables.

Breeder Audrey Steulet-Geiser said 10 of her 36 horses in Cortébert, in the Bernese Jura, had died and the others were in a clinic. Although there had been isolated cases in the past, she told RTS, this year’s outbreak had caught breeders unprepared.

Veterinarian Stéphane Montavon said symptoms can appear suddenly, often within 12 to 24 hours. The first sign is often very dark, tea- or cola-coloured urine, followed by muscle weakness, stiffness and trembling. Affected horses may then collapse with an elevated heart rate and breathing difficulties. The disease is fatal in 75 to 90 per cent of cases.

The resulting losses are not currently covered by cantonal animal disease funds because the illness is a non-contagious poisoning.