GRAZING AND FORAGE PRODUCTION ON NATIONAL FORESTS 



37 



COMPARATIVE FOOD VALUE OF FORAGE IN DIFFERENT STAGES OF DEVELOPMENT 



Not only does the early forage lack " substance," but its food 

 value is less pound for pound than that of the more mature leafage. 

 Figure 14 shows the relative proportion of chemical constituents in 

 leafage of different development and harvested with varying fre- 

 quency, according to analyses made by the Bureau of Chemistry. 

 The data given are the averages obtained for two seasons. Only 



PLANT 

 CUT: 



3 



MOUNTAIN BROME ( Bromus polyanthus) 



PERCENT ' 

 S 10 IS SO SS 30 35 *0 45 



SO 





s 



ETHER [4 times 

 EXTRACT^*™/ 



S 

























CRUDE jf * mes 

 TIBER \j time 



































(4 times 























[/time 















At fTROGE/d* times 

 rREE U 'times 

 EXTRACT {/ time 

















































i 







PLANT 

 CUT: 









VIOLET WHEAT SPAS S (Agropyro 



PERCENT 

 r IO IS 20 ZS JO 3S 



7 



VI 



?/cceum) 



-fS so s 



[ETHER g£- 

 EXTRACT {/ time 



3 

























CRUDE ■{*»%% 

























T/BER \l time 















(4 times 





















PROTEIN \ z t'^es 

 (/ time 















NITROG£n\4 times 

 ERCE < 2 times 

 EXTRACTS t " T >^ 









































1 













RELATIVE CHEMICAL CONSTITUENTS OF HERBAGE HARVESTED WITH MAYING 



FREQUENCY, AFTER TWO YEARS OF TREATMENT 



(The constituents here represented are of primary importance in 



determining the nutritive iso/ue or a pasture plant) 



PLANT 

 CUT; 



3 



MOUNTAIN BROME AND VIOLET WHEAT G/9/ISS 



PERCENT 



s 10 is eo as so ss -to 4s 5 





ETHER U times 

 EXTRACT^ 



% 























CRUDE (^tim es 































FIBER Y'timV 

















[4 times 

 PROTEIN \Z times 

 [/time 

































\ 







NITROCENUtimes 

 FREE \Z times 

 EXTRACT [/ time 









































































COMBINED CHEMICAL CONSTITUENTS OF MOUNTAIN BROME 

 AND VIOLET WHEAT 6~/d4£S (AJ onUZTj 



Fig. 14 



those constituents are here considered that are recognized as being 

 of primary importance in determining the nutritive value of the 

 pasture plants. Those taken into account are : 



Ether extract (oils and fats). 



Crude fiber (cellulose — largely indigestible material). 



Crude protein (Nitrogenous compounds — muscle and tissue building 



constituents). 

 Nitrogen-free extract (carbohydrates — sugars and starches, or heat and 



energy producing constituents). 



