THE PRODUCTION VALUES OF FEEDING STUFFS 683 



784. Values of other cereal proteins. Investigations at the 

 Wisconsin Experiment Station led to the conclusion that not 

 only the proteins of maize but the unbalanced proteins of other 

 cereal grains are distinctly inferior to milk proteins as sources 

 of protein for growth and milk production. 



Hart, Humphrey and Morrison 1 in two comparisons of maize and 

 alfalfa proteins for growing heifers observed a retention of approxi- 

 mately 20 to 24 per cent of the maize nitrogen as compared with 

 much higher figures obtained for milk proteins in later experiments 

 at the same institution. 



McCollum 2 reports a series of trials on young pigs in which the 

 effects of the proteins of maize, wheat and oats, of casein and of skim 

 milk on the nitrogen balance were compared. The protein supply 

 varied in the different trials but the author presents reasons for believ- 

 ing that in no case did it exceed the amount the animal was capable 

 of utilizing in growth, so that the results are not affected in the 

 manner discussed in Chapter XI (468) by surplus protein being 

 katabolized. On the higher protein rations, from 20 to 34 per cent 

 of the resorbed nitrogen was retained in the body of the animal, 

 while, contrary to what would naturally be expected, the percentage 

 retention was decidedly lower on rations supplying less protein. 

 The milk proteins, on the other hand, showed a decidedly higher per- 

 centage retention, viz., for casein 51 per cent and for skim milk pro- 

 teins 66 per cent. 



Hart and Humphrey 3 have compared the proteins of maize, wheat, 

 gluten feed, oil meal, distillers' grains and milk as sources of protein 

 for milking cows (587). Unfortunately, the effects were chiefly on 

 the body protein, so that the only comparison possible is between 

 the algebraic sums of body protein and milk protein. Computed in 

 this way, the average percentage efficiency for three animals was, 

 for milk proteins, 59, for maize 40, for wheat 36, for gluten feed 45, 

 for oil meal 61 and for distillers' grains 60. 



785. Alfalfa proteins. Hart, Humphrey and Morrison in 

 their comparisons of maize and alfalfa proteins just men- 

 tioned (784), found the total nitrogen of alfalfa to show about 

 the same percentage retention in both growth and milk pro- 

 duction as did the total nitrogen of maize. 



In none of these Wisconsin experiments is the maintenance 

 requirement of the animals taken into account in computing 



1 Jour. Biol. Chem., 13 (1912), 133. 2 Ibid., 19 (1914), 323. 



3 Ibid., 21 (1915), 239; 26 (1916), 457. 



