194 CHEMISTRY OF FARM PRACTICE 



habit of growth than the running varieties of cowpeas; 

 consequently, they are more easily cut and harvested. The 

 Tennessee Station has obtained good results from feeding 

 soybean hay to dairy cows; in fact, it proved superior to 

 alfalfa hay. 



144. Composition and Digestibility of Feeds. Table 

 XVII, which is compiled largely from Henry's " Feeds and 

 Feeding," shows the composition and digestibility of a num- 

 ber of feeding stuffs. 



145. The Calculation of Rations. The data of Table 

 XVII and that given in the preceding chapter furnish all 

 the information that is necessary for the calculation of 

 balanced rations. Two concrete examples are here given 

 to show the method and the operations involved in such 

 calculations. 



EXAMPLE 1. The single feed, oats, is nearly a balanced 

 ration for horses; its nutritive ratio is therefore calculated as 

 the simplest illustration. 



The Wolff-Lehmann standard shows that a ration for a 

 horse consists of 24 pounds of dry matter. From Table 

 XVII we find that 89.6 per cent of oats is dry matter. 

 Hence, 24X100^-89.6 = 26.8 pounds, or 26.8 pounds of 

 oats must be fed to furnish 24 pounds of dry matter. There- 

 fore, calculating the nutritive ratio of 26.8 Ibs. of oats, we 

 have the values shown in Table XVIII. 



In the calculation, the pounds of feed are multiplied by 

 the percentage of each nutrient and the result is given in 

 the third column of the table. This result is then multiplied 

 by the coefficient of digestibility, or per cent of digestible 

 material, and the amount of digestible nutrients are placed 

 in each case under the proper head in the table. The diges- 

 tible carbohydrates are added to 2.25 times the digestible 

 fat (because fat is estimated to have 2.25 times the heat- 

 giving power of carbohydrates) and the sum is divided by 

 the digestible protein. The quotient gives the nutritive 

 ratio compared with the digestible protein as the unit. 



