Nov. 4 1918 Net Energy Values of Alfalfa Hay and Starch 



279 



starch may be calculated. Three comparisons are obviously possible on 



the hay and five on the mixed ration. The results are contained in 



Table XIII. 



It may be presumed that, other things being equal, the results obtained 



by comparing the extreme periods — namely, periods 5 and 7 for hay and 



periods i and 4 for the mixed ration — mil be the most accurate. In the 



case of the hay the intermediate comparisons show differences similar to 



those already reported.*^ In the case of the mixed ration and of the 



starch the results show a marked degree of uniformity with the exception 



of those involving period 3. As already noted, the results of this period 



as regards digestibility, methane production, and metabolizable energy 



appear somewhat abnormal as compared with those of periods 1,2, and 4, 



the losses in feces and methane being relatively large and the percentage 



of the gross energy which was metabolizable being correspondingly 



lower. This might be expected to result in a lower heat production. 



If such were the fact, it would tend to explain the marked divergence of 



those heat increments in Table XIII which involve the use of period 3. 



We are inclined therefore to accept the results of the extreme periods — 



viz. 



Hay 999 Calories per kilogram 



Hay and starch i, 200 Calories per kilogram 



Starch i, 692 Calories per kilogram 



as representing most accurately the heat increment caused by the con- 

 sumption of these materials. 



NET ENERGY VALUES 



Subtracting from the gross energy the losses of chemical energy and the 

 heat increment due to feed consumption gives the net energy value as 

 follows (Table XIV) : 



Table XIV. — Net energy values per kilogram of dry matter 



Feed and period. 



Gross 

 energy. 



Losses o' 

 chemical 

 energy. 



Metabo- 

 lizable 

 energy. 



Heat 

 incre- 

 jnent. 



energy 

 values. 



Net 

 metabo- 

 lizable. 



ALFALFA HAY. 



Average 



ALFALFA HAY AND STARCH. 



Average of all 



Average of periods 1,2, and 4. 



STARCH. 



Average of all 



Average of periods 1,2, and 4. 

 Kellner's average 



Cal. 



4,334 



4,284 

 4,276 



4, 105 

 4, 105 

 4, 152 



Cal. 

 2,396 



I, 928 



861 



777 



Cal. 

 1,938 



2, 326 

 2,348 



3, 244 

 3- 328 

 3,051 



Cal. 



999 



200 

 200 



I, 692 

 I, 692 

 1,248 



Cal. 



939 



I, 126 

 I, 148 



I, 552 

 1,636 

 1,803 



Per d. 



48.45 



48.41 

 48.89 



47-84 

 49. 16 

 58.80 



" Armsby. H. p., and Fribs. J. A. OP. ax., 1915, p. 473-475. 



fc From re.sults of i)eriods s and 7. 

 c From results of periods i and 4. 



