The Effect of Raw Soybeans on Blood Plasma Carotene and Vitamin A and Liver Vitamin A of Calves

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Abstract
Four calves, 2 Ayrshires and 2 Holsteins, approx. 14 wk. of age were placed on a vit. A-deficient ration. They were considered to be depleted when the blood vit. A had decreased to less than 5 [mu]g./100 ml. of blood plasma. This level was reached after they were on the vit. A-deficient ration for 35 days. Each calf then was given slightly more than the minimum requirement or 32 [mu]g. of carotene/pound of body wt/day in the form of alfalfa leaf meal for the remainder of the expt. At the end of 49 days, the calves were divided into 2 groups with a Holstein and Ayrshire calf in each group. One group was continued on the basal ration and the 2d group was changed to the test ration which contained approx. 30% ground raw soybeans. This was continued for 170 days. Blood samples for the detn. of blood plasma carotene and vit. A were drawn each week before the feeding of alfalfa leaf meal. At the end of the test period the calves were slaughtered and the livers were mascerated and analyzed for vit. A. The avg. plasma carotene of the 2 control calves during the 170-day period was 25.6 and 22.4 and of the calves on soybeans 18.9 and 17.2 [mu]g./ 100 ml. The plasma vit. A values were 9.6 and 9.1 for the controls and 5.6 and 6.5 [mu]g./100 ml. for the calves on soybeans. The liver vit. A (wet basis) was 9.1 and 9.2 for the controls and 0.7 and 2.8 [mu]g./g. for the calves or soybeans. All values were found to be highly significant.