The animal will die within a few hours from the onset of the third stage. The action of the toxicity has been documented to delay between stages. The first and second stages may be unnoticeable, and then weeks later, the animal may show signs of the third stage and die. In sheep, it is more difficult to diagnose because the stages are not as well defined as in cattle. Toxic amounts of Se can also cause birth defects in offspring from dams fed such levels.
Alkali disease is more chronic than blind staggers, often taking years to manifest itself.
It is caused by feeding on plants and grain that have protein-bound, insoluble selenium. This disease can affect all livestock, but it is detected mostly in cattle and horses. The most effective way of preventing selenosis is to remove the animals from the seleniferous area. Dilution of high Se feeds with low Se feeds in a mixed ration will help to prevent toxicity. Recognition of seleniferous plants, proper land management, and grazing control are all necessary to completely prevent selenosis.