16 



cows you have at all, but certainly you cannot afford to keep 

 them without using what capacity they have to produce milk. 



The dairy cow in a way may be looked upon as a milk- 

 producing machine or factory, and like all factories there is a 

 certain amount of fixed charges that have to be met. With a 

 cow of fair-producing capacity, about one-half her feed is used 

 to maintain the functions of the body without returning any- 

 thing in the way of product. It is the second half of her 

 ration that is used in producing milk. That is, if it costs us 

 $70 to feed a certain cow in milk, about $35 of this sum is 

 used to keep the cow alive. That is fixed charges or the ration 

 of maintenance. This ration of maintenance is practically the 

 same whether the cow be a heavy producer or a low producer, 

 as already pointed out. The high-producing cow is simply one 

 that has a big capacity for using feed above what it costs to 

 maintain herself. The proper feeding of cows in regard to 

 amount is illustrated in the table which follows: — 



Table 9. — - Rations. 



Full Ration. 



Ration of Maintenance. Used for Milk Production. 



o 6 r. 



Three-quarters Ration. 



Ration of Maintenance. Available for Milk Production. 

 d e f 



Half Ration. 

 Ration of Maintenance. 



g h 



The lines from a to c represent the ration for a heavy-pro- 

 ducing cow, which is the one most liable to be underfed. The 

 first half, from a to b, represents the amount of feed required to 

 maintain the animal's body. The second half, from b to c, 

 represents the portion of the feed used for the production of 

 milk. In this case there is no fat being produced on the 

 animal's body and the cow is supposed to have such dairy 

 qualities that she uses all the feed she can digest for milk 

 production. 



The line below represents what would happen if the feed of 

 this animal is reduced one-fourth. The ration of maintenance 

 remains practically the same as in the first case. The amount 



