38 



BULLETIN 1405, U. S. DEPARTMENT OF AGRICULTURE 



It is significant that both violet wheat grass and mountain brome 

 when cut four times in a season generally contained as much ether 

 extract (oil and fat) as when harvested less frequently. The crude 

 fiber in the herbage of violet wheat grass cropped four times in a 

 season was appreciably less than in that of plants harvested less 

 frequently; in mountain brome the herbage removed four times 

 contained considerably less crude fiber than that harvested once, 

 but slightly more than that cropped twice. The protein content, 

 on the other hand, was much greater in the plants whose herbage 

 was cropped four times than in those harvested less -frequently. 

 Protein content was least for the leafage of plants cut once and 

 greatest for that of plants harvested four times. 



In mountain brome the nitrogen-free extract (sugars and starches) 

 was least in the frequently harvested samples and greatest in the 

 herbage removed once. In violet wheat grass the nitrogen-free 

 extract was practically the same in the herbage of plants harvested 

 four times and two times, respectively, and here again it was much 

 the greatest in the herbage cropped once. 



When an average was taken of all the chemical constituents ob- 

 tained from herbage of mountain brome and violet wheat grass 

 (see third series of values in fig. 14), the results were more strik- 

 ing than those of the individual species. The ether extract in the 

 herbage harvested four times was nearly the same as in that cropped 

 twice, but greater than in that removed once. In the herbage cut 

 four times the crude fiber was much less, the protein content was 

 appreciably greater, and the nitrogen-free extract was consider- 

 ably less than in that of the plants harvested less frequently. 



In general, then, the herbage of the frequently harvested plants 

 contained about the same amount of ether extract as that of the 

 less frequently harvested plants but more crude protein, less crude 

 fiber, and less nitrogen-free extract. Naturally the question arises, 

 Is a ton of young air-dry forage worth more or is it worth less 

 than a ton harvested later in the season ? 



Table 12. — Percentage of crude protein in herbage of plants according to 

 march of the season, 1921 



[Analyses by Bureau of Chemistry] 



Plant 



June 24 



Aug. 9 



Aug. 29 



Sept. 18 



Oct. 7 



Nevada blue grass ... 



18.31 



26. 81 

 28.94 



10.25 



10.60 

 13.00 

 18.19 

 13.81 



7.19 

 10.31 

 11.32 

 14.31 

 14.19 



5.33 

 6.81 

 7.10 

 10.78 

 13.90 



4.29 



Violet wheat grass ._ 



4.03 



Letterman needle grass 



5.61 



False cymopterus 



5.61 



Yarrow... .. . . 





8.04 









Average. 



24.69 



13.17 



11.45 



8.78 



5.52 







During the past quarter century investigators have clarified many 

 factors pertaining to the science of animal nutrition, yet our pres- 

 ent knowledge of this profoundly important subject is far from sat- 

 isfactory The price of cottonseed cake, for instance, may be deter- 

 mined largely upon the constituents of the chemical groups already 

 enumerated. As an emergency feed cottonseed cake is most valuable 

 because it is rich in nitrogenous materials. Not long ago it was 



