The Relationship between a Low Carotene Intake and Urinary Excretion of Ascorbic Acid in Dairy Cattle

The possibility of a relationship between vitamin A intake and ascorbic acid metabolism and reproduction in animalshas recently appeared in the scientific literature.reported lower blood plasma and urine ascorbic acid values in a calf on a vitamin A deficient ration than in a check animal Which received 100 micrograms of carotene per kilo of body weight.The storage of riboflavin in the liver of the vitamin A deficient calf was also lower than in the check animal.Sure (23) demonstrated a decreased ascorbic acid content of the blood plasma and tissues of the vitamin A, B1 and riboflavin deficient rat.Sutton (24) fed rats various amounts of vitamin A and noted that urinary excretion of ascorbic acid was less when the rats received 10 and 20 International Units of vitamin A per kilo of body weight, than when 30 units were fed.Phillips (18) reported that the feeding of a high potency shark liver oil to certain dairy herds in a breeding cooperative caused the animals to maintain more nearly normal blood-plasma ascorbic acid values.Boyer and co-workers (4) found lowered blood plasma and cerebrospinal fluid aseorbic aci~d values in calves on a vitamin A free ration.The urinary excretion of ascorbic acid in rats on a vitamin A deficient diet was considerably lower than in control animals receiving vitamin A.On the other hand, Hart, Goss, and Guilbert (6) working with horses demonstrated that a low vitamin A intake carried to a fatal termination did not seriously affect the blood levels of ascorbic acid.Rubin and Bird (21) found the ascorbic acid content of the livers and duodena of vitamin A deficient hens to be as great as that of the same organs of hens fed ample vitamin A. These data, the authors indicate, show that vitamin A deficiency in the mature chicken does not interfere with ascorbic acid synthesis.Jensen and co-workers (7) were notable to increase the plasma ascorbic acid values of dairy cows by feeding vitamin A in the form of shark liver oil.Moore, Berry and Sykes (16) found no particular relationship between blood plasma'ascorbic values and vitamin A intake in calves receiving from 44 to 75 micrograms of carotene per kilo of body weight.Kuhlman and Gallup (12) have pointed out that a satisfactory conception rate was obtained when the carotene intake was at the same level as that required