AGRICULTURAL EXPERIMENT STATION. 69 



It is proposed, therefore, to give in this connection the data and 

 explanations necessary to the calculation of a ration for any 

 specified purpose. 



Whut an efficient nnd economical ration is, and how to obtain it. 



(1) An efficient ration must be sufficient in quantity. 



An animal may be very fitly compared to a machine. If we wish 

 to run a machine we must apply force enough to move its various 

 parts, and then if we use it to perform work we must add to this 

 force in proportion to the work done. In the case of the mowing 

 machine, for instance, it requires a certain amount of exertion 

 on the part of the horses to start and keep it in motion, even when 

 no grass is cut, but when the knives are cutting grass the horses 

 must put forth an additional amount of muscular force. So, if an 

 animal is kept alive, gaining nothing and losing nothing, doing no 

 work either as a draft animal or as a producer of milk or meat» 

 yet maintaining an undiminished bodil}' condition, a certain amount 

 of food will be required to simply run the machine. When the 

 animal is put at some labor, or is used to produce something, then 

 the food must be increased in proportion as the demands upon it 

 are greater. 



(2) A ration that is both efficient and economical must not only 

 be sufficient in quantity, but so compounded that there shall be no 

 w-aste in any direction. It is safe to assert that for a specified pur- 

 pose, milk production for instance, there is some particular combi- 

 nation of food ingredients that to a greater extent than any other 

 secures a utilization of the food eaten. When a milch cow con- 

 sumes a ration in which the amount of digestible protein bears such 

 relation to the amount of digestible non-nitrogenous material that 

 each class of nutrients just fills the place to which it is best adapted, 

 we say we have a well balanced ration. If the protein is fed either 

 in a greater or a less relative quantity, the ration becomes either 

 insufficient or wasteful. 



The truth of these statements will be more clearly seen if we 

 consider the matter somewhat in detail. 



The food which an animal eats is used for several distinct pur- 

 poses. These are : 



(1) The production of new material, either that in the milk or 

 that stored in the body, the latter including the growth of the foetal 

 young. 



