Why is Wagyu beef is the best in the world?

Japanese farmers massage their cows and give them beer and generally treat them like kings. As a result Wagyu beef is said to be the best in the world. You can recognise it by its distinctive marble sheen. Prices can reach £500 per kilo.

http://www.huffingtonpost.co.uk/2015/08/18/cows-drink-beer-wagyu_n_8002222.html