Lord Krishna says in Shrimadbhagwat "I can be worshipped within the cows by offerings the grass and other suitable grains for the pleasures and health of cows and one can worship Me within the Vaishnava by offering loving friendship to them and honouring them in all respects."
Kamdhenu, the sacred cow which grants all wishes and desires, is an integral part of Hindu mythology. This divine cow, which lives in Swarglok, emerged from the ocean milk [ksheer sagar] at the time of Samundramanthan by the Sura and Asura. It was presented to the seven sages by the god, and in course of time came into the possession of sage Vashistha.
It contains influences of all constellations, wherever is a cow ,there is influences of all heavenly constellations, blessings of all Gods are there. Cow is only divine living that has a Suryaketu nadi (vein connected to sun) passes through her backbone. Therefore the cows milk, butter, ghee and golden hue is because of Suryaketu nadi, on interaction with solar rays produces gold salts in her blood. This salt is present in the cow's milk and cow's other bodily fluids, which miraculously cures many diseases. The bull is emblem of Dharma and cow is reprensentative of Earth.
When bull and cow are in joyfull mood. It is to be understood the whole world will be in the joyfull mood. The reason is that the bull helps In production of grains in agriculture and cow delivers the milk.
The miracle food which further can be converted into curd, yougurt, butter and ghee.
Important aspects of cow is that it is an important part of lives of our 70% of the population. Cow dung, urine and milk all are useful for the daily lives of common man in India.
Indian cows are unique in their ability to resist disease, possess characteristics suited to the Indian Agro climate conditions and they have tremendous draught resisting capacities and can walk 24 hours without rest where as these qualities are often found lacking in mixed breeds.