Recently I started to study bull tattoo meaning for my uncle. It came out that these inks are not as simple as they might seem at the first glance. My uncle is a Zodiac bull and he wanted to get a bull tattoo just for fun, though he was smart enough to check the meaning of the ink before actually getting the tattoo. Bull tattoo is not just about horoscope - bulls are considered to be important part of human nature - both in terms of agriculture and mysticism. Imagine that bull tattoo were early symbols of family protection and high fertility, what obviously comes from the role of the cattle in human agriculture.
Also bulls are considered to be often a God symbol (in number of ancient religions - i.e. in Ancient Egypt and Persia) or they can refer to a sacrifice. That's why a bull tattoo meaning is actually multifarious.
My uncle, when he read all about the bull tattoo made a short pause. He said 'I didn't know that a simple tattoo can mean that much'. We discussed this over and over and finally he decided he won't get a bull tattoo, but instead he will try to find something that suits his way of life better. Funny, isn't it?