MINERAL REQUIREMENTS OF CATTLE IN NORTH-EAST
INDIA
193
The question which opens out an interesting field of study is whether such
a large ingestion of potash is associated with any deleterious effect. The litera-
ture on the subject is rather conflicting.
Theiler, Green and du Toit [1927] have given an account of their feeding
experiment in which " higher potassium ration " containing 44 grms. K 2 O and
2 grms. Na 2 O was administered. The K 2 O was later on increased to 64 grms.
The weights of the two animals were 470 lb. and 450 lb. at the start and increased
to 1,000 and 1,130 lb. in about two years. The authors remark that on " in-
creasing the total K 2 O to 64 grms. (ratio 32 to 1) Heifer 878 died within a few
days with symptoms of tymphanitis, but showed no characteristic post-mortem
lesions upon which to base a definite diagnosis ". Its companion became ill,
lost appetite and declined steadily in weight for two months, recovered and gave
birth to a weak small calf which died five days later while the mother suffered
from "severe mastitis, following retention of the after-birth, did not respond
to treatment and was killed in extremis ". The authors are, however, inclined
to believe that " no disease has been manifested " and that " so far as growth
is concerned a relatively high proportion of potassium to sodium appear to have
little influence ". Green [1935] in a more recent communication adheres to the
views of his associates and states that " no naturally occurring disease has been
proved to be due to deficiency or imbalance between them ". On the other
hand Orr [1925] considers that " the ratio of sodium to potassium affects the
assimilation of both calcium and phosphorus ". The behaviour of lime assimila-
tion as exhibited in the present experiment (vide balance figures) would rather
seem to support the latter statement.
At the same time the ingestion of potash under the present experiment was
considerably higher than those of Theiler, Green and du Toit [1927]. In their
case the maximum ingestion was 64 grms. per 1,130-lb. or 28.3 grms. per 500-lb.
as compared to 53 to 89 grms. in the paddy straw feeding. As the balance figures
have shown there has been a higher lime requirement under this feed. It is,
therefore, very likely that the assimilation of lime is probably closely related to
the quantity of potash. Hawk [1931] remarks that potassium has an important
relation with calcium in maintaining the normal rhythm of contraction and re-
laxation of heart muscles. The classical experiment of Ringer [1880-82] on the
perfused heart show that minute changes in the concentration of calcium or potas-
sium in the perfusing fluids have a profound effect on the activity of the heart
A deficiency of potassium will prevent the heart muscles from relaxing and an
excess will relax so completely that it stops beating. Remi and Müller's [1931]
experiment with respect to rachitic symptoms associated with high potash intake
has been already referred to under lime. The experiments of Richards [1927]
show that the addition of potassium salts to a ration of cereal in the case of grow-
ing pigs leads to a decreased retention of nitrogen, phosphorus and calcium.