CHOICE OF FORAGE CROPS 55 



required. Broadly speaking, the reliability of the results 

 will depend upon the uniformity of the animals as to size, 

 sex, age, used in the experiment ; upon the number of 

 individuals used; and upon the length of time the ex- 

 periment continues. 



But few experiments in which two roughages have been 

 compared fulfill the above requirements, but the results 

 secured in American experiments with grass or legume 

 hays are cited in connection with the feeding value of each 

 particular hay. 



Perhaps the most extensive data from direct feeding 

 trials are those secured in Denmark and Sweden in con- 

 nection with the feeding of dairy cows. In these trials 

 the standard of value or feed unit is one pound of dry 

 matter in corn, wheat, barley, palm-nut meal or roots, 

 with which the value of other feeds as determined by 

 actual feeding is compared. 



The results thus far reached lead to the conclusion 

 that for milk production there is required to equal 1 feed 

 unit 2 to 3 (average 2.5) pounds hay ; 6 to 10 (average 8) 

 pounds silage, green clover or mixed green grasses ; 8 to 

 12 (average 10) pounds mangels, rutabagas and carrots; 

 10 to 15 (average 12.5) pounds turnips ; 12 to 18 (average 

 15) pounds beet leaves. 



Woll has determined tentatively that the following 

 amounts of American feeds probably equal 1 feed unit; 

 namely, 1.5 to 3 (average 2) pounds alfalfa or mixed hay, 

 oat hay, oat and pea hay, barley and pea hay or redtop 

 hay ; 2.5 to 3.5 (average 3) pounds timothy hay, 'prairie 

 hay or sorghum hay ; 3.5 to 6 (average 4.2) pounds corn 

 stover, stalks or fodder, marsh hay or cut straw. 



It by no means follows that the relative value of these 

 feeds for dairy cows represents their respective value for 



