320 SCIENTIFIC FEEDING OF ANIMALS 



to find out whether the several groups give the same 

 quantities of milk of equal fat content. If this is 

 not the case the animals must be rearranged or 

 fresh ones introduced until perfect agreement 

 between the several groups is attained. 



If, for example, maize and coarsely ground corn 

 are to be compared regarding their influence upon 

 milk production, then both these feeding-stuffs 

 must be given in the basal ration, and three groups 

 of cows are necessary. If the agreement of these 

 groups is settled the real experiment begins, and 

 for a month all three groups are given the basal 

 ration. Then follows another period of thirty days, 

 during which the three groups are fed differently, 

 group A receiving only the ground corn in place of 

 the maize, group C maize instead of the corn ration, 

 and group B the maize-corn ration unchanged. 

 In the third period, which again lasts thirty days, 

 a return is made to the same rations which were 

 given in period i. In an investigation of this 

 kind, where equal quantities of maize and corn 

 were compared with one another, there was given, 

 along with constant quantities of other feeding- 

 stuffs, the following quantities per head per 

 day : — 



ist Period. 2nd Period. 3rd Period. 



A, B, and c. a. B. c. A, B, and c. 



Corn . . 1-09 kg. 2-12 i-o6 — 1-03 



Maize . . 0-89 kg. — 1-06 2-12 1-09 



