Hinduism, the main religion practised in India, encourages appreciation of the natural world and reverence for all forms of life. The cow is particularly sacred to Hindus, most of whom are vegetarians. For this reason the slaughter of cows is illegal in most Indian states. The cow is a maternal symbol in India because it provides more sustenance for a family if kept alive than if killed for its flesh. It provides milk, yoghurt, butter and ghee -- all of which are generally considered an essential part of a vegetarian diet. (Ghee, or butter-oil, is widely used as a frying medium.) Cows are also important as "workhorses" on family farms, particularly in terms of their ability to plough fields.