Why can sulphate of ammonia favour hypomagnesaemia?
Under the conditions of this experiment, one single dressing of sulphate of ammonia profoundly altered the mineral composition of the animal’s blood, giving rise, as BARTLETT says, to “spectacular” hypomagnesaemia 3 and several cases of grass tetany. It may be wondered why sulphate of ammonia exercises this marked depressing effect on the blood serum of the grazing animal, thus possibly helping to trigger off tetany. As has just been said, the sulphate of ammonia in this particular instance did not alter the magnesium content of the herbage.4 It did, however, very considerably increase the content of crude protein, which is normal. Now, it has been seen (Fig. 15) that this high content of crude protein in herbage increases considerably the amount of ammonia produced in the rumen, and thus favours hypomagnesaemia 5 and tetany. This explanation is only relatively correct, however, because other nitrogenous fertilizers (particularly the nitrates) have a less marked effect on hypomagnesaem
