Who was the pioneer of the White Revolution?

In animal husbandry,if two closely related animals are mated for a few generations,it results in loss of fertility and vigour. Why is this so?

In the last how many years has milk and milk production developed as an important trade?

What was developed during the White Revolution?

Animal husbandry deals with

$A$: Milk is a valuable product used as a nutritious food.
$R$: It is the fresh natural secretion of the mammary glands of female mammals for the nourishment of their young ones.