Observations on the Carotene Content of Some Typical Pasture Plants

Only in recent years has vitamin A been considered a limiting factor in the well-being of cattle under ordinary feeding conditions. Hart and Guilbert (8) reported evidence of vitamin .A deficiency in range cattle after unusually prolonged dry feeding periods. Results such as reproductive failure, and dead, weak or sick calves were more common when the feed was ample, and complete except in vitamin A potency. They concluded (6) that the storage of vitamin A during the green feed season is sufficient to carry range animals safely through the dry-feed periods of ordinary duration. In discussing dairy cattle feeding, Woodward and Nystrom (15) state that vitamin A is the vitamin most likely to be deficient. Meigs and Converse (11, Calves could not be successfully raised on milk produced from rations based on poor quality hay. Converse and Meigs (2) have shown that in raising calves on restricted quantities of whole milk the limiting factor is the vitamin A content of the butter fat rather than any other inherent qualities of the fat.