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Summary The data obtained in this series of studies show that the minimum carotene requirement of growing calves is eleven micrograms per day per pound body weight. This level of carotene intake was sufficient to maintain growth and to prevent the usual vitamin A deficiency symptoms. The adequacy of this amount of carotene, however, depends upon the source of supply of carotene. While it appears desirable that the intake should be considerably above this amount it was surprising to find that increases above that level did not result in marked improvement in growth rate. The order of availability of carotene to calves from the various sources studied is as follows: 1. Carotene concentrate, 2. Alfalfa hay, 3. Corn silage, 4. Corn meal, 5. Timothy hay, and 6. Alfalfa molasses silage. |
