Substitution of Roots for Concentrated Foods. 485 



to compare the cost of one pound of butter fat with rations I and III. 

 The average cost of one pound of butter fat with ration I for one feeding 

 period, was 20.2 cents; when these same cows were fed ration III, the 

 cost of one pound of butter fat was 20.7 cents. The average cost of 

 one pound of butter fat with the check groups for both years was 20.6 

 cents. The same conditions which tended to influence the value of one 

 pound of dry matter in mangels as compared with the dry matter in 

 grain, as cited above, would have the same influence in increasing the 

 cost of production of one pound of fat. Taking these into consideration, 

 and since the cost in the two cases, 20.2 and 20.7, was so nearly the same, 

 we seem warranted in the assumption that ration III was just as econom- 

 ical as ration I, and that the dry matter in mangels can be substituted 

 for at least one-half the usual grain ration, pound for pound, when 

 mangels are produced for $4.50 per ton and grain is sold at the prices 

 quoted in Table IV. 



(b) Comparison of dry matter in mangels with dry matter in grain 

 with rations II and III. In ration II, mangels were fed as a succulent 

 food, and in ration III silage was fed as a succulent food. In comparing 

 the results obtained in feeding rations II and III, this fact must be 

 kept in mind, because, as has been shown, the dry matter in mangels 

 was perhaps a little more valuable for feeding purposes than the dry 

 matter in silage. Table XXVII has been prepared from Tables XII, 

 XVIII, XIX, and XX to show these comparisons of rations II and III. 

 Fifteen comparisons were possible between these two rations. In eight 

 cases, ration II was fed first, and in the other seven ration III was fed 

 first. As before, the total grain replaced and the amount of dry matter 

 in the mangels which were fed in place of grain were determined. On 

 comparing these amounts, it was found that 2079.9 pounds of dry 

 matter in grain was replaced by 2562.9 pounds of dry matter in mangels, 

 with a loss by the change to mangels of 36.42 pounds of butter fat. 

 At first it may appear that -it would take 1.23 pounds of dry matter 

 in mangels to replace one pound of dry matter in grain. But it will 

 be noted from Table XXVII that 149.7 pounds less dry matter was fed 

 in the succulent feed (silage) when ration III was given. Also, on 

 referring to Table XXIII it will be seen that not only was the dry matter 

 in the mangels more efficient, pound for pound, than the dry matter 

 in the silage, with a good gain of butter fat, but it was more efficient 

 even with 529.8 pounds less dry matter at the same time. Taking these 

 facts into consideration, perhaps the gains in butter fat, shown in these 

 comparisons, were not entirely due to the grain in ration II, but may 

 have been due more to the fact that mangels were fed as a succulent 



