Relative Value of Carotene from Alfalfa and Vitamin A from a Dry Carrier Fed at Medium to High Levels to Holstein Calves

Using a group of forty-eight 63-day-old male calves, the authors set out to determine quantitatively the relative value of carotene from alfalfa and of vitamin A from a dry carrier, fed at medium to high levels.Blood and liver concentrations of vitamin A and vitamin A depletion time were used as criteria.Editor.Both the minimum vitamin A and provitamin A, carotene, requirements of calves have been well established (~, 14, 15).These have been based on intakes of vitamin A or carotene to maintain satisfactory growth or prevent the occurrence of night blindness, squamous metaplasia in the parotid gland or duct, papillary edema, or increased spinal fluid pressure.It has been recognized that these vitamin A or carotene requirements based on the above criteria do not permit appreciable vitamin A storage in the dairy calf.Although there was little concrete evidence in favor of feeding higher levels of vitamin A or carotene than necessary for normal growth or prevention of deficiency symptoms, the feeding of high enough levels of vitamin A and/or carotene to provide sufficient vitamin A storage has been indicated for the purpose of eliminating deficiencies during subsequent periods of low intakes of these substauces aud/or poor absorption due to scours (5, 16).These were possibly some of the reasons that the National Research Council's Recommended Allowance (11) for carotene was approximately 2.0 to 6.0 times greater than the minimum requirements established for dairy calves on the basis of normal growth and prevention of deficiency symptoms.