Biochemical aspects of bovine ketosis

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Abstract
The sera of approximately 70 Jersey cows, half of them suffering from bovine ketosis, were analyzed for their content of 12 selected blood constituents. These included 4 members of the citric acid cycle (pyruvate, citrate, [alpha]-oxoglutarate and succinate). Known micromethods were adapted for estimating small amounts of the above compounds and a new method for the estimation of succinic acid was elaborated. A relationship was established between the two principal biochemical characteristics of the disease, i.e., the high concentration of serum ketone bodies and the very low concentration of glucose, so that either phenomenon can be used to assess the severity of the disease. No significant differences between normal and diseased animals were found for amino-N, urea, ammonia and cholesterol. In all pathological cases the pyruvate and [alpha]-oxoglutarate in serum were hundred per cent above normal and this was paralleled by a strong depression of the amounts of citrate and of succinate. It was concluded that in bovine ketosis there may exist an interference with the citric acid cycle, notably with those reactions in which pyruvate and [alpha]-oxoglutarate are converted into citrate and succinate respectively. From the known similarity of the mechanism of the 2 reactions a deficiency in cofactors common to both was suspected, such as coenzyme A and adenosine triphosphate; the compatibility of such a deficiency with certain symptoms in ketonemia is discussed.
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