The Effect of Vitamin A Stores and Carotene Intake of Beef Cows on the Vitamin A Content of the Liver and Plasma of their Calves

Abstract

Mobilization of stored vitamin A and carotene by lactating beef cows on a low plane of carotene intake was inadequate to provide sufficient vitamin A for their calves. Vitamin A content of milk, and to a lesser degree carotene, seem much more closely related to dietary carotene intake during lactation than to differential liver stores resulting from various levels of carotene intake prepartum. Supplementation of low carotene rations with 300 mg. of carotene per cow daily during lactation resulted in normal carotene and vitamin A levels in the plasma and livers of suckling calves. The rate of depletion of the liver stores of the cow during 5 months postpartum was also decreased.