FEEDS AND FEEDING 



569 



pose. Calculating the dry substance and digestible nutrients of this ration 

 from Table I, the following results are obtained: 



Comparing the nutrients of the trial ration with the requirements of 

 the standard, it is seen that the trial ration is a little below the standard 

 in dry substance and protein, and a little above it in carbohydrates and fat. 

 Thus the third step is to modify the trial ration so that its nutrients con- 

 form to the standard. Consequently, a feed which is high in protein and 

 low in carbohydrates should be substituted for part of the ation. Inas- 

 much as it is not desirable to lessen the bulk of the ration as the dry 

 substance is already a little low, one may substitute two pounds of linseed 

 meal for two pounds of the oats of the ration. The ration then contains 

 the following nutrients: 



The nutritive ratio is: 



11.4 + 2.25 X 0.7 or 1:6g 

 1.9 



This ration, except that it is a trifle low in dry substance, comes very close 

 to satisfying the standard. Of course, in many cases, especially until one 

 has had considerable practice in the calculation of rations, the trial ration 

 may have to be modified several times before the ration conforms with 

 the standard. However, by applying his practical knowledge, the stock 

 feeder should not have much difficulty in calculating balanced rations. 



In view of modern investigations, certain modifications must be made 

 to the Wolff-Lehmann standards to adapt them to American conditions. 

 In practically every instance the amount of diy substance prescribed is 

 10 to 20 per cent too high. The protein prescribed is from 10 to 40 per cent 

 too high, the greatest difference being in the case of fattening and working 

 animals, and, consequently, the nutritive ratio is too narrow. Very little 

 attention should be given to the fat content of the ration, it being con- 

 sidered satisfactory if the requirements for protein and carbohydrates are 

 fulfilled. 



