Sheep farmers in Gelderland have moved 106 pregnant ewes from their herd in Renkum across the border to Friesland after 23 animals were killed in a suspected wolf attack.

Ellen van der Zweep, whose sheep were bitten to death last week, said: ‘We received all kinds of well-intentioned advice to protect our sheep against the wolf. There were even people who offered to sleep with the herd.’

But she and her husband decided to move the animals to Friesland, where they can give birth to their lambs in safety.

There are thought to be between 30 and 35 wolves living in the Veluwe nature reserve in Gelderland.

A wolf-resistant grid, which the herders had installed for €12,000, was not enough to prevent the attack.

‘You have to make sure that a fence is high enough. At the same time, wires must also be stretched to prevent the wolf from getting under it,’ a spokesperson for the province told media outlet de Gelderlander.

Glenn Lelieveld of the Mammals Association said there are other solutions besides fencing, such as keeping animals in a night pen and using watchdogs.

‘We as a society have to help the farmer with that,’ said Lelieveld. ‘It all takes a very long time.’