The buffalo in this movie could be anything in real life. It's a depiction of human greed. Could be money, power, religion, land, lust or a buffalo itself given it excites man. If set free, they can bring chaos.
Millions of years into human evolution and yet, inside each of us hides our earliest ancestors masked by a thin shell of modern civility and humanness. Jallikattu succeeded in showing us how fragile this shell could often be. That's the brilliance of this movie. The art in it!