Rate of Absorption of Carotene and of Vitamin A from the Alimentary Tract of Dairy Calves. I. Effect of Method of Administration

Summary Carotene and vitamin A given at the rate of 1000 I.U. per lb. of body weight of calf were administered, respectively, by nipple feeder, stomach tube and gelatin capsule. Comparisons of initial blood plasma carotenoid and vitamin A levels with those 2, 4, 8, 12 and 24 hr. after feeding the vitamin substances were employed as criteria of the rates of absorption. Carotene and vitamin A dispersed in milk by homogenization and fed by nipple were absorbed more rapidly than similar preparations administered by stomach tube. The rates of absorption of carotene and of vitamin A from concentrates administered by gelatin capsules were somewhat less rapid than those resulting from the foregoing procedures. The rate of absorption of vitamin A by calves restricted to whole milk was less rapid than the rate of uptake by the same calves after having received a diet of reconstituted buttermilk, hay and grain concentrates for approximately 8 wk. Conversely, the rate of absorption of carotene was more rapid under the former dietary regime than under the latter.