256 VITAMIN D GROUP 



cient sunlight to make a dietary source of vitamin D unnecessary. How- 

 ever, the report on the nutritive recommendations quote Bechtel et at} as 

 finding the vitamin D requirements of young beef calves to be about 300 

 I.U. per 100 pounds of live weight. 



Sheep, like beef cattle, also spend considerable time on the range and 

 probably need no dietary source of vitamin D. Lambs away from sunlight 

 should be given this vitamin, and the Committee on Animal Nutrition 

 recommends a daily allowance of 250 to 300 I.U. of vitamin D per 100 

 pounds of live weight. In a similar manner, the working horse in all prob- 

 ability needs no dietary source of vitamin D because it is exposed to direct 

 sunlight for hours at a time. Where horses are confined away from the light 

 of the sun, it is recommended that the daily allowance be 300 I.U. per 100 

 pounds of live weight. There is no experimental information available on 



TABLE XIP 

 Recommended Daily Allowances'' of Vitamin D for Swine 



Breeding stock 



Pregnant females 

 and breeding boars Lactating females 



Market stock Young Adults Gilts Adults 



Live weight, lb. 50 100 150 200 250 300 500 350 450 

 Vitamin D 150 265 340 375 415 300 375 550 625 



" Adapted from Recommended Nutrient Allowances for Swine: A Report of the Committee on 

 Animal Nutrition, National Research Council. 

 International units per animal 



the horse, but the recommendations are based on knowledge concerning 

 other animals. 



It is to be remembered that these recommendations are not minimal 

 quantities, but a rather liberal allowance has been made for a margin of 

 safety. 



Harris et al.^ found that for foxes on a basal diet which contained 0.82 

 I.U. of vitamin D per gram the addition of 200 I.U. per kilogram of body 

 weight "was not above the limit for best physiological efficiency." They^ 

 have also studied the requirements of minks for vitamin D, and they found 

 that 0.82 I.U. per gram of food was sufficient, provided that the calcium 

 to phosphorus ratio was between 0.75:1.00 and 1.70:1.00. 



5 H. E. Bechtel, E. T. Halhnan, C. F. Huffman, and C. W. Duncan, Mich. Agr. Expt. 



Sta. Tech. Bull. 150 (1936). 

 « L. E. Harris, C. F. Bassett, and C. F. Wilke, J. Nutrition 43, 153 (1951). 

 ■• C. F. Bassett, L. E. Harris, and C. F. Wilke, /. Nvtrition 44, 433 (1951). 



