Clinical investigation into the possible role of ascorbic acid in cows affected with acetonaemia

Abstract

1. Estimations of blood ascorbic acid, glucose, total acetone bodies and free acetone were made on nineteen normal dairy cows during the prepartum and postpartum period. Ascorbic acid levels fluctuated markedly between .080 and .620 mgms/100 ml. with an average range of .294 to .456 mgms/100 ml. Levels appeared to decrease at parturition and increase after the fourth week postpartum. These trends were not significant. Glucose levels increased significantly at parturition, but in over 50% of cows they dropped below 30 mgms/100 ml. at some stage during the first eight weeks of lactation, and some dropped below this level two to six weeks prepartum. There was no statistical correlation between ascorbic acid and glucose levels. Total acetone bodies increased significantly during the third week of lactation but there was no concomitant rise in free acetone.

The free acetone levels appeared to increase in cows showing transient hypoglycaemia. One animal which developed ketosis during the study did not show any drop in blood ascorbic acid levels during the onset of the condition.

2. Liver glycogen levels increased transiently in two out of three normal bovines after ascorbic acid injection, but there was no effect on blood glucose levels. ACTH and Prednisolone raised blood glucose levels and decreased eosinophils. Only ACTH showed a glycogenic effect. The combination of ascorbic acid with these drugs did not produce a synergistic effect.

3. Ascorbic acid saturation tests on normal lactating cows and ketotic cows were compared. Excretion of ascorbic acid in the latter appeared to be excessive, and there appeared to be retention of ascorbic acid after injection in two cases. Repeating the experiment on one case after it had recovered from ketosis demonstrated that individual animals could react inconsistently to the test. The observation that polyuria is a clinical feature in the early stages of ketosis was discussed.

4. Two out of seven cases of ketosis injected with ascorbic acid alone recovered. One may have been a spontaneous recovery. Five of the cases showed a favourable response to initial injections of ascorbic acid. Free acetone levels decreased, glucose levels fluctuated markedly and milk yield increased slightly after injection. All cases showing a favourable response had high initial eosinophil counts. The improvement was not maintained with subsequent injections of ascorbic acid and conventional treatment had to be adopted. Ascorbic acid had no glycogenic effect in one case of ketosis. The response in one case to injection of ascorbic acid combined with AGTH was disappointing.

Certain original clinical observations such as a marked drop in eosinophil levels in two ketotic cows prior to treatment, and the excessive loss of body fluid being responsible for clinical symptoms of dehydration, loss in weight and dry faeces in ketosis have been discussed.