From a friend:
it’s not that just because they provide us with milk, cow dung, that cows are worshipped…
Cows, in Hindu religion, is a representative of mother Earth (as stated in Krishna’s Bhagvat). Her four legs stand for four goals of human life - dharma, arth(Material), kaam (desires), and moksh (liberation). She’s venerated as she’s believed to house 33 crores of gods and goddesses!
Just yesterday, in South of India, Cow Pongal was celebrated.