This thesis, after a brief review of the
literature dealing with the effects of cobalt
deficiency in animals and especially the physiological
rôle of cobalt describes experiments designed to
clarify certain aspects of these problems.
The conclusions arrived at from the present
investigation are as follows: -
(a) That lambs grazing cobalt dressed pasture
eat more grass than lambs grazing cobalt deficient
pasture of equal nutritive value as far as proteins,
fats and carbohydrates are concerned. This was
established by grazing experiments with groups of
lambs equipped with a suitable harness which allowed
of the daily measurement of faeces excreted.
(b) That the difference in the amount of
nutrients eaten by the two groups would suggest that
the clinical symptoms of 'Pining' - the diseased
condition associated with cobalt deficiency - were
those of malnutrition.
(c) That the digestion of crude fibre by sheep
on cobalt deficient diets is of a low order and can
be increased by the oral administration of cobalt
(d) That the digestion of the other organic
nutrients of the ration is not materially altered by
a low cobalt intake.
(e) That a daily diet containing 0.02 mg. of
cobalt does not allow of the animal being in a state
of positive cobalt balance but that the addition of
3 mg. of cobalt per day changes a negative cobalt
balance to a positive one with the animal retaining a large proportion of the 3 mgs. of. cobalt.
(f) That the major portion of cobalt ingested is
excreted in the faeces and only minute amounts in
(g) That all the data obtained in the present
series of experiments would support the theory that
the physiological function of cobalt is connected
with r»mi nation.