the symbolism of the shiva-shakthi is to be understood here, not just in india but through out the world there are many primitive cultures with similar beliefs and practices, man as a primitive being sees "life" is a product of the union (be it the union between male and the female or the union between the sun and the earth that caused fertility) so the primary assumption of well-being is fertility. you will have to understand it here that humans go to god for fertility and well-being so did the ancient people think. hence they started worshiping the elements that leads to fertility be it phallic structures or the forces of nature. hence shiva and shakthi are none other than the symbolic interpretations of male and female genitals. the lingam and yoni.. the union of both leads to fertility. and inorder to please the forces in which the ligam is to be considered and supreme which needs to be nourised with energy every time. hence there was sacrifices of animals and even humans in ancient periods, as such many animals and humans were killed before the phallic structures for the nourishment. as such we see a ox sitting before the linga, in ancient time the bull was sacrifices and later on the sacrifices moderated to castration before the linga as offering the male energy to god, and the purpose of castrating ox for agricultural purpose was also fulfilled. and in recent time ie. after buddhism and christianity the practice of such rituals were moderated and stopped.. still in some parts of the country the tradition goes on..
