More than 100 Jersey cows died in mid-December over the course of a few days and vets think they now know the most likely cause.
The death of the cattle at Woodlands Farm in St Helier nearly two months ago was most likely from botulism.
Botulism is a rare but serious illness caused by a toxin that attacks the body's nerves and causes difficulty breathing, muscle paralysis and even death.
No toxins were found in the cows’ feed during government-commissioned tests, but there was traces of bacterial spores that produce toxins.
Cattle are extremely sensitive to botulism.
Susana Ramos, Chief Veterinary Officer, says despite no toxins being found, the spores paired with the exclusion of notable diseases and signs reported at the farm combined suggest botulism.
"Botulism is notoriously hard to test for, and diagnosis is often based primarily on the clinical signs and by ruling out other possible causes."
The results from the cow feed came back to the government, from the UK, on Thursday night (9 February).
Willie Peggie, Director of Natural Environment, says we were aware from the outset that a conclusive laboratory result might not be achievable.
"We have been able to rule out a number of causes, by a process of elimination but have not been able to identify the toxin."
Together, they believe there is no reason to indicate there could be any risk to other animals, or the general public.
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