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

Following are breeds of cows,$EXCEPT$:

$A$ group of animals which are related by descent and share many similarities are referred to as:

Which of the following is not an objective of animal breeding?

$A$: Fish meal is a rich source of protein for cattle and poultry.
$R$: Fish meal is prepared from the non-edible parts of fishes such as tails,fins,and bones.

Which is the world's highest milk-yielding breed of cattle?