Worshipping the cow is a custom in Hindu tradition. This is Called Gopooja. Much importance is given to gopooja in our PURANAS. These PURANAS tell that the four Samudras (Chathu Sagaras) are in the milk of the Cow (Goksheeram). The Vedic Scholars say that all the worlds (Samastha Bhuvanaas) are hidden in all parts of the Cow.If we Observe the details of the parts of the cow, the various devidevathas who dwell in the different parts of the cow are ----Lord Siva dwells in the forehead and horns of the cow.
That is why if one takes the water which is sprinkled on the cow's horns it is Equalant to the effect of Water of Triveni Sangamam. Not only that, it is as effective as worshipping Kasi Visweswaradu with Siva Ashtotharam, Sahasranamalu and with the leaves of Maredu (Bilwadalalu).It is also said that Lord Subrahmanya resides in the nose part of the Cow, Worshipping that nose part is to prevent the loss of children. To get relief from all diseases is worshipping the ears of the cow as it is the place of Aswini Devathas The Sun and Moon are near the eyes of the Cow. So Worshipping the eyes of the Cow is Beneficial to Obtain the Knowledge of light by driving away the darkners of ignorance and also to get Wealth and Prosperity.
To get Children early, Worshipping the tongue of the cow as it is the Place of Varuna Deva, to get good Education, Worshipping goddess Saraswati, who is in the of the Cow, and on the right side of the face of the cow resides Yama and on the leftside of the face Dharmadevathas reside. Worshipping these two parts is important to attain Moksha.In the Udder of the cow are the four Purushardhas. So it is to be Worshipped to get Dharma, Artha, Kama and Moksha. As Indra resides in the neck part of the Cow, it is to be worshipped to beget children. Nagadevathas are at the end of the Hooves of the Cow and they are to be worshipped to avoid the danger from the snakes. The Hooves are the Places of Gandharvas and apsaras, they are to be worshipped to Obtain all prosperity, So in all aspects, it is Considered that worshipping the cow is the worship of all Devidevathas.