A deficiency in which nutrients leads to White Muscle Disease in sheep?

White Muscle Disease in sheep is primarily associated with deficiencies in selenium and vitamin E. These nutrients play crucial roles in maintaining muscle health and overall growth in animals. Selenium functions as an antioxidant, protecting cells from damage caused by free radicals, and is vital for the proper functioning of muscle tissues. Vitamin E, similarly, is important for muscle health and works synergistically with selenium to prevent oxidative damage. When there is an inadequate supply of these nutrients, it leads to the degeneration of muscle fibers, which manifests as White Muscle Disease characterized by stiffness, weakness, and potential mortality, particularly in young lambs.

In contrast, the other options involve nutrients that contribute to different health issues. While calcium and magnesium are essential for bone health and metabolic processes, a deficiency in these would not lead specifically to White Muscle Disease. Zinc and iron are important for various bodily functions, including immune response and oxygen transport, and deficiencies would lead to different health complications. Vitamin A and D are crucial for vision, skin health, and calcium metabolism but are not directly linked to the muscle degeneration seen in this condition. Therefore, the correct answer highlights the specific nutrient deficiencies that directly impact muscle integrity in sheep.