294 STOCK FEEDING 



nutritive value of the food used. If we subtract the amount of the 

 nutrients found in the manure from the amount of the same nutri- 

 ents in the food, the result will show the amount of digested mate- 

 rial. According to some authorities a milk cow, a fattening steer, 

 or a work horse will generally need each day about two pounds of 

 digestible protein, twelve or thirteen pounds of digestible carbo- 

 hydrates, and approximately a half pound of digestible fats. The 

 season of the year, the condition of the animal, and many other 

 things are to be taken into consideration, so that these estimates 

 are only approximately correct. 



Nutritive Ratio. According to Professor Bailey the amount of 

 energy yielded by fats is about two and one fourth times as much 

 as that given by an equal weight of sugar or starch ; that is, the 

 fats are considered two and one fourth times as valuable for food 

 stuffs as carbohydrates. The nutritive ratio is the ratio of the 

 digestible protein to the digestible carbohydrates plus two and 

 one fourth times the digestible fat, and the operation may be 

 expressed very conveniently in the following formula : 



Carbohydrates + (Fat X 2.25) 



Protein i 



For example, if the amount of digestible carbohydrates = 34 

 and the amount of digestible fat = 1.42, while the amount of 

 digestible protein is about 6.00, we have: 



34 + (1.42 X 2.25) 34 + 3.195 37.195 

 6.00 6 6 



= 6.199 = 6.2 approximately. 



That means the nutritive ratio is 1 to 6.2 for this particular kind of 

 feed. 



A ration is the amount of food given an animal during a day 

 or any stated period. Rations are classified as balanced, narrow, 

 medium, and wide, according to the proportion of carbohydrates 

 and fats to the amount of protein. 



A balanced ration is one in which the proportion of carbohydrates 

 and fats to the amount of protein has been so adjusted or balanced 

 as to give the most satisfactory results with the least possible 

 expenditure. The ordinary limit for a well-balanced ration is 



