Potassium Metabolism of Domestic Ruminants—A Review

Ruminants and other herbivores normally consume amounts of potassium (K) greatly in excess of their dietary requirement, which is probably no more than about 0.5% of the ration, even for rapidly growing sheep or cattle. Ruminants appear to be well adapted to metabolize large amounts of K. The cation concentration in the rumen fluid has an important effect upon ruminal digestion. Under conditions of Na deficiency, K may replace Na as the major cation in saliva. Large oral doses of K administered rapidly have been fatal to cows. Potassium may be partially responsible for death of calves suffering from diarrhea, Hypomagnesemia grass tetany is the only pathological situation related to high K intakes, and this relationship is not clear. The K 40 content of the whole body is being investigated as a means of estimating lean-body mass. This method shows promise of being a rapid and precise method of nondestructive measurement of body composition.