THE NITROGEN-FKEE EXTRACT OF FEEDING STUFFS. 



659 



Since the crude fiber is i)artially digested, and tlie nitrogen-free 

 extract is incompletely digested, and since analysis does not show the 

 actual feeding' value of cither of these constituents, their estimation 

 separately miglit be regarded as unnecessary, Tlie percentage of each 

 found by analysis shows nothing- of nuich importance. Hence, it might 

 be considered sufficient to deterunne the crude fiber and nitrogen -free 

 extract together by dift'erence, deducting the sum of the fat, protein, 

 asli, and water from 100. As a nmtter of fact, I>. Konig considers 

 their separate determination of comparativelj^ little value, and Atwater' 

 groups the constituents of human foods nnder protein, fat, ash, and 

 carbohydrates. 



TJie nitrogen-free extract approximntcJy equal to the .snm of the digesti- 

 hJe crude fiber and digestible nitrogen-free extract. — Tlie feeding and res- 

 piration experiments of Henneberg and Btohmann, and of others, have 

 shown that the amount of crude fiber digested agrees approximately 

 with the amount of nitrogen-free extract left undigested. Hence the 

 percentage of nitrogen -free extract found by the Weende method is 

 practically equivalent to the sum of the digestible nitrogen-free extract 

 and the digestible crude fiber. Henneberg and Stohmann^ state, for 

 instance, that "the undigested part of the nitrogen-free extract com- 

 pensates for the digestible part of the crude fiber, and is to be regarded 

 as liginn; the digestible part bears the closest relation to the Avater- 

 soluble constituents of coarse fodder." 



This rule follows with more or less exactness frojn the original data 

 given by Henneberg, as well ns from that furnished from time to time 

 by various investigators, and a study of the data presented in Dietrich 

 and Konig's excellent compilation suffices to confirm the rule. The 

 following data from tliat source will serve to illustrate: 



lieUiliou hetu-een tlw total nitrofjen-free extract and thr »iim of the iHficsiihle /iher and 



n itro{/ni -free ejrtracl. 



liTiiiii- 



ber 



in Oiet- 



ricli 

 and Ko- 

 nig's 

 tables. 







18 



20 



24 



29 



07 



129 



135 



168 



176 



178 



185 



225 



232 



236 



249 



SiibstiUMc (dry). 



Bactylia glomoraf a 



Wbeiit bejiiuuiiij; to sboot 



Fodder corn 



^leado w y ras.s 



fireen clover 



Beet leaves 



^leadow bay (average) . . . . 



Mountain bay 



Wheatstraw 



Oat straw 



Corn stover 



Pea straw 



I'otatoes 



Beets 



Wbeat 



Corn 



Fonnd by the 



Weende metbod of 



analysis. 



Crnde 

 liber. 



Per cent. 



27. 02 

 25. 75 



28. 03 

 33. 12 

 30. 27 

 14.35 

 2!l. 21 

 27. 12 

 43. 00 

 43.04 

 31.98 

 41.03 



2.75 

 7.68 

 2.19 

 2. 55 



Digestible niate- 

 rial.s calculated from 

 feeding experi- 

 ments. 



Crude 

 iiher. 



Per cent. 



15.93 



16.74 



16.03 



20. 20 



16.05 



8.32 



17.54 



10.81 



23.65 



24. 90 



17.59 



10.01 



1.51 



4. 22 



1.10 



1.28 



Nitrogen 



free 

 extract. 



Percent. 

 35. 34 

 31. 89 

 34. 43 

 29.85 

 29. 40 

 31. 40 

 31,83 

 .35. 18 

 17. 55 



22. 91 



23. 88 

 21.48 

 82. 18 

 09. 2(i 

 75.72 

 74.60 



Sum of 

 digestible 

 ]>nrtions of 

 iriule liber 

 and nitro- 

 gen-free 

 extract. 



Per cent. 

 51.27 

 48.63 

 50.40 

 50. 05 

 46.05 

 39.72 

 49.37 

 51.99 

 41.20 

 47.87 

 41.47 

 37.49 

 83.09 

 73. 48 

 70.82 

 75.88 



' U. 8. Dept. A,ii;r., OCfict^ of ICxperinieut Stations liiil. iM. 

 -Weender Beitriijje, vol. 2, pp. 454, 4.5.o. 



