Well i've done a few thousand miles walking in Britain and there seem to be more and more aggresive cows about and they are all colours and of breeds that I've never herd of before. As farmers give up on milk production and Frezians (spelling?) they are bringing in all sorts of other breeds, very conservation worthy i'm sure, but how well do we know the temprement of some of these other animals.
Highland cattle, for example, may be gentle but I'm not going to argue with a ton of beef with a pair of two and a half foot daggers on its head and no proof of its pedigree.