Although this is a common assumption, it is incorrect. Hindus do not worship cows, but instead hold them in high regard, respecting the gifts that they give to humankind. If you think about it, cows are constantly giving to humans; they give us milk, which we drink to become strong adults and often consume throughout our entire lives. In an indirect way, cows also give us butter and yogurt, since these are both made from milk. Additionally, cows are important in Hinduism because the pancagavya-milk, curds, ghee (clarified butter), urine, and dung)-come from the cow and are used in Hindu ritual worship ceremonies; sometimes cow dung is also used as one of the materials for making a tilak (forehead marking) in India. Finally, Hindus believe that cow dung is a natural cleanser and therefore they believe that cows provide humans with a natural cleaning and sanitation product. Cow dung can also be used for building purposes (houses, etc.), used in place of firewood as fuel, and is often a major source of energy for many Indian homes.
Because they give so much and never ask for anything in return, cows are believed to be symbols of the earth and Hindus often refer to them as the "mothers of the earth." For this reason, Hindus believe cows to be a gift from God; therefore, consuming beef and veal is considered sacrilegious in Hinduism. Cows are also associated with the Hindu God Krishna, who is known as Govinda (protector of the cows), as well as the Hindu God Shiva, whose vehicle is Nandi the bull. So, cows are not worshipped in India, but instead are simply highly respected for their mythological association with the Gods and, more importantly, for their life-sustaining gifts.