Manganese in the Nutrition of Young Dairy Cattle Fed Different Levels of Calcium and Phosphorus

Abstract

In a study of manganese in the nutrition of dairy calves five test diets, four experimental and one conventional type (control), were fed to a total of 15 calves randomly assigned within breeds to dietary groups. The experimental basal diets (B) contained less than 1 p.p.m. of manganese. Three other experimental diets were formulated by adding, respectively, to the basal diets manganous sulfate supplying 50 p.p.m. of manganese (BMn), 3 to 5% monocalcium phosphate (BCaP) and a combination of the preceding supplements (BMnCaP). A conventional type calf diet was fed for comparative purposes. Growth rate and serum magnesium levels of the herd-diet group were significantly greater than for calves fed experimental diets. Supplemental manganese did not affect significantly the levels of calcium, inorganic phosphorus, or the activity of alkaline phosphatase in blood serum. Supplemental manganese apparently effected the following physiologic responses of the calves: Partially counteracted the deleterious effects of monocalcium phosphate on weight gains during the latter stages of the feeding periods. Depressed serum magnesium levels, particularly when the manganese was fed in conjunction with monocalcium phosphate. Increased blood levels of manganese, but increases were not statistically significant when the diet contained supplemental monocalcium phosphate. Increased life span while monocalcium phosphate decreased it, but neither affected mortality, which was 100% for calves fed experimental diets. Calcified deposits were found on post-mortem examinations in the cardiovascular or pulmonary system of calves in all experimental groups except B. The results of this study suggest that the need for dietary manganese by calves is extremely low and that increased amounts of calcium and phosphorus intensify the needs for dietary supplements of manganese. © 1955, American Dairy Science Association. All rights reserved.