196 Journal of Agricultural Research voi. x, N0.4 



mulation of information on the physiological behavior of feeding stuffs 

 than on the attempts to bring out new mathematical expressions of 

 feeding standards. 



These experiments further show the limitations of the theory of a 

 "balanced" ration as now expressed and indicate the very great im- 

 portance of other factors besides protein and energy in the successful 

 diet. It was indeed surprising to find that the common wheat kernel 

 had a low toxicity; but such factors as toxicity, growth-promoting 

 substances of unknown nature, proper balance of salts, indicate how 

 complex the problems of animal nutrition really are and how neces- 

 sary it is that these factors be clearly exposed in order that we may 

 place the various feeds in their proper category. We have pointed 

 out how a material of low toxicity, such as the wheat kernel, may be 

 used with success. A good roughage like a legume hay was an admir- 

 able "antidote." Even com meal and a poorer roughage like com 

 stover served to offset the detrimental effects of a large mass of wheat 

 embryo. This also illustrates how an adjustment of the normal factors 

 of nutrition may conceal the presence of the detrimental factors. 



It is important to keep constantly in mind that the disclosure of 

 either a nutritive deficiency or the presence of an abnormal factor in 

 a common natural foodstuff should not necessarily condemn its use. 

 It should, however, emphasize the need of combining it in the ration 

 with those other natural products which will either supply abundantly 

 the deficiencies or act as an "antidote" to any inherent toxicity, 



SUMMARY 



This paper summarizes the results of further studies of the physio- 

 logical value of restricted rations. The data presented are limited to 

 observations on growing and reproducing heifers and are especially 

 concerned with the effect of the nutrients from the wheat and com 

 plants. 



Restriction to the wheat plant as a source of "balanced" nutrients 

 (wheat grain plus wheat straw) did not sustain growth with Holstein 

 heifers. Such animals also failed to show oestms and could not be bred. 



Marked pathological conditions resulted, such as blindness, feeble and 

 emaciated condition, and abnormal excitability followed by collapse. 

 Evidence is presented which fixes the responsibility for such a con- 

 dition on two factors in the ration: (i) poor salt mixture and (2) inher- 

 ent toxicity in the grain. 



Improvement of the ration could not be made by additions of salt 

 alone. 



By the use of com stover as a roughage in place of the wheat straw, 

 growth was sustained but reproduction was only partially successful, 

 dependent upon the stamina of the mother. Where reproduction was 



