« You have two cows » is a typical joke on Capitalism and some well-known countries.
It is a form of political satire on various political, economic, etc. systems.
Some other variations:
Socialism: You have two cows. The government takes one and gives it to your neighbour.
Communism: You have two cows. You give them to the government, and the government then gives you some milk.
Fascism: You have two cows. You give them to the government, and the government then sells you some milk.
Nazism: You have two cows. The government takes both and shoots you.