210 PRINCIPLES OF FARM PRACTICE 



Standardizing a ration. A ration is standardized by com- 

 paring it with the standard for the class of animals to be 

 fed, and then correcting it to make it conform to the standard. 

 The ration to be corrected is called the trial ration. The trial 

 ration may be one in actual use or may be a mere guess as 

 to the probable needs of the animal for which it is intended. 

 The following steps are necessary in standardizing a ration: 

 First, by means of a table giving the composition of digestible 

 feeds, determine the total dry matter, protein and carbo- 

 hydrates in the trial ration; second, find the difference be- 

 tween each item of the trial ration and the corresponding item 

 of the standard ration; then correct the trial ration to corre- 

 spond closely, but not necessarily exactly, with the standard. 

 An example will show how these steps are actually made in 

 standardizing a ration. 



A standard ration for cattle, per 1000 pounds live weight, 

 first period, contains these nutrients: protein, 2.5 pounds; 

 carbohydrates and fats, 16.1 pounds. 



Suppose a ration of 20 pounds of red clover hay and 10 

 pounds of dent corn is being fed to a 1 2oo-pound steer. Con- 

 sidering this as a trial ration the nutrients as determined from 

 a table of digestible nutrients will be as follows: 



Carbohydrates and 

 Trial Ration Protein (pounds) 



20 Ibs. clover hay 1.42 



10 Ibs. dent corn .75 



2.17 

 Standard ration for i2oo-pound 



steer 3.00 



Difference-. .83 



The difference shows the deficiency in protein to be rela- 

 tively greater than in carbohydrates. Therefore the correction 



