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

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Abstract
Ascorbic acid excretion in normally fed heifers varied from 25.8 to 110.5 mg. per day. When fed 5 gms. of chlorobutanol for 10 days, normally fed heifers excreted 210-399 mg. of ascorbic acid per day. Ascorbic acid excretion of pregnant heifers receiving a ration low in carotene was 4-6 times greater than in similar animals normally fed. The feeding of 5 gms. of chlorobutanol for 10 days to pregnant heifers receiving a ration low in carotene stimulated the excretion of ascorbic acid very little. The chlorobutanol caused an increase in plasma ascorbic acid values of the normally fed pregnant heifers but not in similar heifers receiving a low carotene ration. Dairy [male][male] excreted varying amts. of ascorbic acid regardless of the level of carotene intake, except when made severely deficient, in which case there was a decrease in ascorbic acid excretion. Normally fed [male][male] excreted considerably more ascorbic acid per kilo of body wt. than normally fed [female][female]. It still remains to be shown that a low carotene intake under practical farm conditions has a depressing effect on ascorbic acid synthesis to the extent of altering breeding efficiency.