A herd of rare cows has been culled because they were too aggressive.

Farmer Derek Gow says the Heck cow descended from cattle specifically bred by Nazi scientists between the world wars, to resemble the extinct ancestors of all cattle, aurochs.

As a result of their aggressive behaviour, Gow had all but six of his herd destroyed:

"We have a lot of people coming here [to the farm]."

“With the original group, you simply couldn't walk through the fields. Some of the individuals were very aggressive.”

"No matter where they were, they would come over and try to kill you."

This clip was taken from 5 live Breakfast on Tuesday 6 January 2014.