The Production of High Vitamin A Milk by Diet

Abstract

The vitamin A content of the butterfat obtained from cows on a diet high in fresh alfalfa was considerably increased by the administration of shark liver oil in daily doses of approximately 700,000 I.U. although lower amounts were ineffective. The vitamin A in butterfat averaged 113 I.U. after administration of the vitamin A supplement at a level of 1,400,000 I.U. daily. In one cow, the level reached 170 I.U. per gram which value was also noted a month later. The increased amounts of vitamin A in the butters persisted without diminution over a 5-month period during which the experiments were continued. There is a marked decrease in carotene which occurs even when doses of shark liver oil, too small to cause an increase in the level of vitamin A in milk, are fed. No toxic-symptoms were noted and the cows remained in good nutritional condition as reflected by the increased production of milk and butterfat. The present experiments emphasize the lack of correlation between color of the milk and its vitamin A content.