40 DAIRY FARMING 



extract, by the digestible protein. In the ration calculated 

 above the nutritive ratio equals 13.17 + (2.25 X -87) -j- 

 2.48 = 6.1 ; that is the nutritive ratio in this case is i :6.i. 



When the amount of nitrogenous matter is small as 

 compared with the non-nitrogenous matter, the ration is 

 said to be ''wide." When the reverse is true, the ration 

 is said to be "narrow." 



Proportion of Roughage and Concentrates. Accord- 

 ing to our feeding standard, a cow yielding 22 pounds of 

 milk requires a ration containing 16 pounds of digestible 

 nutrients and a total of 29 pounds of dry matter (digest- 

 ible and indigestible). This amount of dry matter means 

 that the ration must have a fairly definite bulk. Where 

 the ration contains a great deal of rich concentrates in 

 proportion to roughage, it is apt to lack in bulk. On the 

 other hand a ration containing a large proportion of corn 

 stover, oat straw and similar roughage, is likely to make 

 the ration so bulky as to make it impossible for a heavy 

 producer to consume enough of it to obtain the required 

 nutrients. 



In the ration calculated on page 38 the proportion of 

 roughage and concentrates is about right. Under average 

 conditions a cow yielding 22 pounds of milk should have 

 a ration composed of about two-thirds roughage and one- 

 third concentrates. For greater yields it is best, as a 

 rule, to increase only the concentrates to meet the require- 

 ments of the additional flow of milk, thus making the pro- 

 portion of concentrates to roughage greater the larger 

 the yield of milk. 



Fertilizing Constituents of Feed. These are nitro- 

 gen, phosphoric acid, and potash. Feeds rich in these 

 constituents will produce manure correspondingly rich 

 in them. In the selection of feeds, therefore, some atten- 



