At least 70 cows have died following an outbreak of botulism on a farm in Carmarthenshire.
It is believed the disease came from the carcase of a rotting animal in the grass silage being fed to cows at Cwrt Malle Farm – a super dairy in Llangynog that houses around 2,000 cattle.
The Animal Health and Veterinary Laboratories Agency (AHVLA) has begun an investigation into the outbreak.
Farm owner Howell Richards said the experience had been unpleasant but staff were now moving on. The contaminated feed has since been removed and the cattle replaced.
Hugh Pennington, professor of bacteriology at Aberdeen University, said botulism was a distressing disease for the animals.
He explained: “The bug is a tough bug in the soil, it’s very rare in humans, it’s not spread from animals to humans, but it’s very unpleasant for the animals because it’s a powerful poison that actually paralyses the animals – and if an animal is sick like that it has to go.
“It’s nothing to worry about from the human point of view at all, but clearly the agricultural people will be keeping a very close eye on this hoping this is not a problem that is going to get any worse.”
Botulism is usually caused by animals coming into contact with the litter of broiler chickens, according to the AHVLA. It can also affect sheep.
To prevent disease, farmers are advised to store litter securely, well away from livestock and to prevent access to birds.