Studies in the metabolism of cobalt

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 salts.(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/ 44. 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 the urine.(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