http://www.wonderquest.com/cow.htm
If you watch Braveheart closely, during the scene when Wallace and his men cross the river and Wallace hides inside of a dead Scottish cow, you'll see what I think are modern day analogues of the Aurochs.
Scottish Highland cattle closely resemble them and Herefords [when unpolled] are capable of growing massive and long *forward pointing* horns that greatly resemble the cattle pictured in cave art.
Their horns grow in roughly the same shape and position as elephants tusks do, for help in visualizing it.
Just my tuppence tossed in....:)
Except of course that an aurochs was sized more like a rhino than a cow. :)