There is strong relationship between blood serum concentration of selenium and
functioning of dairy cows mammary gland. There are many interrelations of the nutrients and
effects of supplementing selenium in daily food of cows. The cow`s uptake and requirement
of selenium vary due to the lactating months and health status. On the basis of these results it
can be conclude that selenium has importance in proper functioning of the mammary glands
of cows, and in improving milk quality.