Vitamin D

Some conservative investigators suggest that some vitamin D supplement might well be fed during the milk-feeding period or during the winter months. Several experiments, however, indicate that supplementary vitamin D is seldom needed. I. W. Rupel, G. Bohstedt, and E. B. Hart, working at the Wisconsin Agricultural Experiment Station, reported that calves on rations devoid of vitamin D, but exposed to all available sunlight both summer and winter, gained nearly as much weight as calves fed a vitamin D supplement. S. I. Bechdel, K. G. Landsburg, and O. J. Hill at the Pennsylvania station reported that 2.5 pounds of sun-cured alfalfa hay supplied an adequate amount of vitamin D.

At Beltsville 50 calves received carotene and skim milk after 3 or 4 days of colostrum feeding, and therefore had to depend from birth on sun-cured hay in the ration and exposure to sunlight for their supply of vitamin D. Most of these calves had very little exposure to sunlight during the first 6 months of life and several of the calves had very little exposure to sunlight during the first full year. Some four or five of the calves kept for a full year out of all direct sunlight showed only mild rachitic symptoms—slightly roached backs during a period when they were eating little hay, but the symptoms disappeared when they ate more hay.

Cod-liver oil, which supplies both vitamins A and D, was fed experimentally to calves in the Holstein and Jersey breeding herds at Beltsville. These calves are always fed whole milk until about 30 days old and skim milk for at least 6 months. A suitable grain mixture is fed, with a limit of 3 pounds daily. Alfalfa hay, usually of U. S. No. 2 grade, was fed free choice in hayracks. Alternate calves in each breed, 70 in all, were fed 20 cubic centimeters (4 teaspoons) of cod-liver oil daily. The addition of the cod-liver oil showed no advantage in gains in body weight at 3 months or at 6 months of age. Monthly observations showed no difference between the two groups as to thickness, mellowness, and flexibility of the hide, or as to the animal's health, vigor, or condition.

If dehydrated or barn-dried hay or grass silage constitutes the only roughage, while the calves are kept out of the sunlight, growing animals will probably require a vitamin D supplement. If heavy grain feeding materially lessens the amount of hay consumed, they might get rickets. In other words, it appears that additional vitamin D is needed by the growing calf only under unusual conditions of feeding or management.

Vitamins B and C and Nutritional Scours

Several experiments have indicated that the cow manufactures vitamins B and C in adequate amounts, and that the calf receives enough of them in the milk until its capacity to synthesize them is sufficiently developed to take care of its own needs. Paul H. Phillips, at the Wisconsin station, reported that the calf at birth was deficient in vitamin A, ascorbic acid (vitamin C), and niacin (nicotinic acid). He reported also that 90 percent of calf scours was due to nutritional deficiencies and could be prevented by feeding these substances during its first 2 weeks of life. As a result of this report, many drug houses now are advertising, for the preventions of scours, capsules containing the Wisconsin recommendation—vitamin A, 5,000 International units; vitamin D, 500 International units; vitamin C ( ascorbic acid) , 250 milligrams; and niacin (nicotinic acid) , 50 milligrams.

The rather startling claims concerning the efficacy of these supplements for the control of calf scours led several investigators in Ohio, Michigan, and Cornell University to initiate rather extensive check experiments with more than 1,200 calves. The trials were made in experiment station and university herds, in other State institution herds, and in New York in some private herds. Alternate calves in each herd were fed the supplements, and the other calves served as controls. Capsules of two colors were usually used. Capsules of one color contained the supplement and capsules of the other color contained an inert oil. The herdsmen were not told which capsules contained the supplements. The reports, by W. E. Krauss, for Ohio and Michigan, and A. A. Spielman, for New York, did not indicate any favorable effect on the control of scours from feeding the "scour-prevention capsules."