Poisoning by which of these elements causes blind staggers alkali disease in livestock?

Ans: C. SeleniumBlind staggers are no longer believed to be caused by selenium but by sulfate toxicity due to the consumption of high-sulfate alkali water and/or high sulfur-containing forages.Since Sulfate is not mentioned in Question we will go for selenium.Excess sulfate (>1% of diet) leads to polioencephalomalacia and the classical signs of blind staggers.Blind StaggersThis syndrome may occur within a brief period (a few days to a few weeks) after the animal has begun to take in very high dietary levels of selenium. The symptoms of this condition are: impaired vision, a depressed appetite, and wandering in circlesProlonged oral exposure of cattle to elevated dietary selenium (Se) is associated historically with 2 clinical syndromes:Alkali disease."Blind staggers".These two syndromes are not necessarily independent of one another. An animal may have only symptoms of one or the other or a combination of the symptoms of both. Both are associated with cardiac and skeletal muscle damage as well as hepatic damage.