गाय हमारी माता है (Cow is our mother)
गाय दूध देती है (Cow gives milk)
These are two lines which comes on top of my mind when I reminiscence my schooldays. So why are Cows revered in Indian Culture? Cow is the universal mother. She feeds her milk not only to her calves but also to the children of the world. Milk is considered to be among the highest forms of food - Sattvic (purity). One cow in a generation benefits 475,000 people through her milk, butter and offspring.
It is not only in India where Cows are revered. They are greatly respected in Nepal and Burma too. People in the ancient India were primarily pastoral. They relied on the cows for milk and dung. Cow dung was one of the main fuels in rural India and also served as a fertilizer. Cow dung and cow urine were used as disinfectant to clean up homes (still used in Tamil Nadu).
Despite its big size, a cow is a calm and non-threatening animal - you could see cows quietly roaming Indian roads. Hindus have always appreciated the tolerance, patience and calmness of the cow. Thus, cows stood for the goodness and considered a representative of Dharma. Also, a cow's affection to its calf is a beautiful thing and Vedas greatly appreciated this bonding.
Some may question why only ban on beef and not on other animals/birds. In the most liberal country- the US, dog's meat and cat's meat are banned. People have special bonding with them and treat them as children. Similarly, in India Cows are considered as mother. Hindus have special bonding with her. In every Hindu household, the first food that is cooked is for Cows.
The First war of Indian Independence, famously known as the Indian Rebellion of 1857 happened because the grease used on the cartridges of the rifles had tallow derived from beef. The sepoys had to bite the cartridge open to release the powder in their rifles. This was clearly offensive to the Hindu sepoys which led to the mutiny.
It is all about gratitude. The holy status of Cows are because of the deep respect and love. Cow is known to be "Aghanya"- never to be killed.
Mahatma Gandhi said,"I worship her and I shall defend her worship against the whole world" and that, "The central fact of Hinduism is Cow protection."