Livestock deaths prompt warning over acorn poisoning risk

Vets and farmers have warned of a sharp rise in cattle and sheep poisoning cases caused by a bumper crop of acorns and sycamore.

The 2022 weather pattern of a cold, wet snap in mid-spring followed by a hot summer have combined to produce the high yields from oak and sycamore trees.

Early autumn gales have made the situation worse by bringing down large quantities of seeds while still green.

Acorns are always potentially fatal when consumed, but grazing ruminants and horses find them more appealing in their green state before they ripen and harden.

See also: Opinion: Don’t be cowed into taking cattle off the land

The Farmers’ Union of Wales (FUW) drew attention to the heightened risk after one Welsh farmer lost 12 cattle that had consumed green acorns blown down by gales.

The union said it had been alerted to an unusually high number of cases this autumn and warned forecasted high winds would see the issue continue.

Acorn advice

It pointed to guidance issued by the National Animal Disease Information Service (Nadis), which says acorn poisoning is one of the most common causes of poisoning among livestock.

According to Nadis, clinical signs include depression, rapid weight loss, tiredness, vomiting and diarrhoea.

The outlook is poor for animals that have developed poisoning through consuming acorns. If eaten in sufficient quantities, acorns can cause birth defects in in-calf cows and prove fatal.

The majority of deaths associated with acorn poisoning are due to kidney failure caused by toxins known as gallotannins.

Nadis advised that the best way to avoid poisoning was by anticipating outbreaks.

Areas should be fenced off around oak and sycamore trees, while cattle should be removed from pasture following heavy acorn falls.

Where poisoning is suspected, animals should be removed from the source as soon as possible and veterinary advice sought, it added. 

Cattle deaths

However, the warnings came too late for one Welsh cattle rearer, who lost 12 New Zealand Friesians to acorn poisoning.

Gruff Williams contract rears heifer replacements at Cefn Leisiog, on the Lleyn peninsula in north-west Wales.

“I noticed one or two were looking under the weather and was concerned they had eaten something, but I checked the field and there was nothing visible,” Mr Williams told Farmers Weekly.

The farm vet was also stumped by the symptoms. The animals’ condition continued to worsen and the first heifer died on 8 October.

A post-mortem found the remnants of acorns, pointing to poisoning as the cause.

© Gruff Williams

Although there were no oaks around the field where the symptoms first occurred, there were trees next to pasture in a field grazed by the group of 65 heifers a week earlier.

“I looked up and saw that the oak trees were laden with acorns. I had never seen so many and the ground was covered.

“It is 60 years since my father bought the parcel of land and we have never seen anything like this before or had a problem,” he said.

He reported that once the animals had ingested the toxins there was nothing that could be done to save any of those affected.

Over the next days, the toll rose to 12 heifers. In all, the animals took almost two weeks to die.

With strong winds forecast, Mr Williams has moved cattle indoors and will fence off the areas in the pasture in the future.