It has been seen that the risks of tetany diminish greatly when the magnesium content of the herbage exceeds a certain limiting value. By their very nature the different species have different contents of magnesium, with the result that the proportion in which they are present in the flora affects the magnesium content of the herbage as a whole. Table 25 shows the magnesium content of different species. Magnesium content of various grasses and legumes Timothy, for example, is particularly low in magnesium, and it has been confirmed in the U.S.A. that timothy hay, which is fairly widely used in some regions, can help to produce hypomagnesaemia in the stall.
White clover contains twice as much magnesium as timothy.
The high magnesium content of red clover, a very popular forage crop for dairy cows in Normandy, should likewise be noted. On the average, legumes can be said to contain more magnesium than the Gramineae. This is demonstrated by Table 26 and Table 27. The extremely low and almost non-existent sodium 3 contents established by these German and British investigators gives rise to some anxiety. The serious physiological consequences of this deficiency have already been referred to.