90 PRINCIPLES OF FEEDING FARM ANIMALS 



ratio. The nutritive ratio, although it does not state the 

 amounts of the different nutrients in a feedingstuff, does 

 indicate the relative proportion of the nutrients present. 



The nutritive ratio is the ratio of digestible nitrogenous 

 nutrients to digestible non-nitrogenous nutrients in a feed 

 or ration; i.e. it is the ratio of digestible crude protein to 

 digestible carbohydrates and digestible fat. The nutritive 

 ratio may be regarded as expressing the relative value of 

 feeds as flesh-, and as fat-, or energy-formers. The nutritive 

 ratio indicates at a glance whether a feedingstuff is suitable 

 for growing, fattening, work, or milk-producing animals, or 

 whether it should be used in combination with other feeds, in 

 order to have the proper proportion of nutrients in the ration. 



Inasmuch as fat is about 2 J times as valuable for fat produc- 

 tion as protein and carbohydrates and, as was stated on page 

 19, as fat contains about 2\ times as much energy as the same 

 amount of protein and carbohydrates, the amount of digestible 

 fat is multipHed by 2\ and added to the amount of digestible 

 carbohydrates, and the sum is then divided by the amount of 

 digestible protein. The first term of the ratio is always ''1," 

 while the second term is obtained by the following formula : 



digestible carbohydrates + 2 ^ (digestible fat) ^ ^H t 

 digestible protein 



The nutritive ratio is written as ''1:6" or " 1 : 14," or 

 whatever it may be. It is read as " one to six," or " one 

 to fourteen." Thus one finds the nutritive ratio of corn 

 as follows : 100 pounds of corn contain 7.8 pounds of digest- 

 ible protein, 66.8 pounds of digestible carbohydrates, and 4.3 

 pounds of digestible fat. Then, substituting in the above 

 formula : 



