266 . THE BREEDING OF ANIMALS 



conclude that " High calcium rations, as compared with 

 low calcium rations, had no effect whatever during a 

 single gestation period on the size or calcium content of 

 the skeleton of the foetus. The skeleton is not increased 

 in any dimension by a wide variation in the amount of 

 calcium fed the mother." 



253. Size and vigor of foetus as influenced by corn and 

 wheat rations. The particular rations fed to breeding 

 animals may profoundly influence the character of the 

 foetus. It is not enough that the prospective mother 

 should receive a ration containing the right proportions 

 of protein, carbohydrate and mineral substances, but 

 these minerals must be of the kind of substances which 

 are known to satisfy the nutritive necessities of the ani- 

 mal. A most interesting demonstration of this fact was 

 made possible through the valuable work of Hart, 1 McCol- 

 lum, Steenbock and Humphrey at the Wisconsin Experi- 

 ment Station. In May, 1907, these investigators began 

 feeding four heifers a ration of corn meal, corn stover and 

 gluten feed, all corn products. Another group of four 

 was fed wheat meal, wheat straw and wheat gluten, nutri- 

 ents derived entirely from the wheat plant. The mate- 

 rials supplied in each ration were proportioned in such a 

 manner as to furnish each group of animals a well- 

 balanced ration in accordance with the accepted feeding 

 standards. The feeding continued for two years and 

 accurate records were kept of feed consumed, gains in 

 live weight, and physiological condition of all animals in 

 the experiment. 



1 Hart, McCollum, Steenbock and Humphrey, "Physio- 

 logical Effect on Growth and Reproduction of Rations Balanced 

 from Restricted Sources," Research Bulletin No. 17, Wisconsin 

 Experiment Station. 



