With their long horns and shaggy coats they may look magnificent, but a British farmer has been forced to reduce the size of his herd of “super cows” descended from beasts associated with Nazi Germany because they are too aggressive.

Derek Gow created a stir in 2009 when he imported 13 Heck cattle – linked to the extinct European wild ox, the aurochs – and set them to graze on his Devon farm.

He successfully bred the cattle and at one point had more than 20 roaming his fields but has cut the herd to six because most of the creatures turned out to be too dangerous to handle.

Gow said: ”The ones we had to get rid of would just attack you any chance they could. They would try to kill anyone. Dealing with that was not a lot of fun at all. I have worked with a range of different animals from bison to deer and I have never come across anything like these. They are by far and away the most aggressive animals I have ever worked with. Some were perfectly calm and quiet and they are the ones we have kept. The others you could not go near.

“We made sure no one went near them so there were never any incidents. To get them into the trailer to get them off the farm we used a young and very athletic young man to stand on the ramp and they charged at him before he quickly jumped out the way.”

Heck cattle were created in the 1920s and 30s by the German brothers Heinz and Lutz Heck, two zoologists who wanted to recreate the aurochs, an important beast in Teutonic mythology. Some of the Nazi leaders dreamed of allowing the animals to roam free so they could once again be hunted.

Gow, who brought the cattle to the UK to study and as subjects for photography, said: “When the Germans were selecting them to create this animal they used Spanish fighting cattle to give them the shape and ferocity they wanted. The reason the Nazis were so supportive of the project is they wanted them to be fierce and aggressive.

“As far as being a commercial breed is concerned, they have little value, but they are a significant animal from a conservation point of view.”

He could find no takers for the aggressive animals he needed to get rid of so had to send them off to an abattoir. Quiet has returned to the farm.

“Since they have gone it is all peaceful again. Peace reigns supreme,” he said. “Despite these problems, I have no regrets at all. It has been a good thing to do and the history of them is fascinating.”