The cow is the mother of all creatures. Cows are verily the mothers of the 33 crores of demigods that administrate creation in the material existence throughout all universe. The cow is the goddess of the gods and refuge of all auspiciousness. Cows bestow every kind of happiness and for this reason, they always are worshippable.
Not only the cow provides us milk, ghee(clarified butter), dung for fuel, urine for medicine, and many more but also the source of all prosperity. The cow is the mother of mankind so Hindus call her GAU MATA or KAMADHENU GAU.
Lord Krishna also states in Srimad Bhagvad Gita about Kamdhenu cow-Among cow I am the wish fulfilling cow.