Though cross breeding, to an extent, has increased the milk production, the true genetic characteristics of these native breeds have been lost. What is the most critical completion of the passage?

The cross breeds are hardy and resistant to disease by nature.

Yet the dream of white revolution is far away.

A number of common breeds are gradually becoming extinct.

Though cross breeds are robust and have good milk yield, they are not suitable as draft animals.

Artificial insemination has played havoc with the native breeds.