Abstract: Selenium has an enormous impact on the living organisms. This element is also important for its biological role. In the Republic of Azerbaijan, unlike other examples identified, biogeochemical regions are affected by selenium deficiency. In Azerbaijan according to the studies on amount of selenium in malnourished animals especially in buffalo offspring are lack and white muscle and muscular dystrophy based diet (nutritional muscular dystophy) diseases are seen. The animals have white muscle disease feeding on forages and this forage has 8 times lower amount of selenium than healthy animals forages. Water buffaloes found on the swamp during the day eat reed living in water. This causes the disease. But sheep eat milk vetch after the first snow fall. Therefore, white muscle disease in sheep is not visible in Azerbaijan.