470 IOWA DEPARTMENT OF AGRICULTURE 



on account of the larger amount of sugar in the plant at this stage and 

 the consequent greater production of acid and carbonic acid gas. 



It is better, therefore, to leave corn in the field as long as possible, 

 even until after frost, rather than to ensile it too soon. Corn which 

 has been absolutely frozen will make good silage, as freezing will not 

 destroy the enzymes, and there will be plenty of opportunity for the 

 entrance of acid-forming bacteria during the silo filling. Of course the 

 corn must not be left in the field so long after being killed by frost that 

 it begins to mold, or the leaves become so dry that they are brittle. 



The following experiment furnished evidence of the fact that frozen 

 corn makes good silage. Several stalks of corn were cut and placed in 

 an artificial ice machine, so that they were solidly frozen for 12 days. 

 They were then thawed out, chopped, and ensiled as usual. The con- 

 sequent evolution of carbonic acid gas, and the formation of acid and 

 alcohol were about the same in amount as in the normal corn silage. 

 The appearance and odor were normal and good. Of course, after corn 

 is frozen, the plant cells are killed and after thawing, will spoil. There- 

 fore the corn should be ensiled as soon as possible thereafter. 



RAPE Sn.AGE. 



Also with the cooperation of Mr. Evvard, the writer has succeeded in 

 making good silage from rape and from mixtures of rape with other 

 materials. Rape and alfalfa are among the very best pasture crops for 

 swine, on account of their luxuriant growth, high protein content, and 

 efficiency as growth producers. If rape proves to be as efficient in the 

 form of silage as when green, its value to swine growers will be greatly 

 increased. 



Rape is rather more difficult to ensile than corn, because it contains 

 more water and a higher percentage of sugar, as well as certain sub- 

 stances containing sulphur, which are likely to form disagreeable products 

 if the fermentation progresses too far. The higher sugar content also 

 tends toward the development of more acid than in corn silage. The silage 

 made from the entire rape plant and from rape leaves was, however, 

 pleasant in taste and odor, but very sour. If the same precautions are 

 observed as in making corn silage, such as packing well into an air-tight 

 silo of the proper shape, there should be no great difficulty in preserving 

 rape. 



The mixtures which were made with rape and other plant materials 

 were much better, however, especially in the case of added legumes, such 

 as alfalfa and red clover. The rape supplies to the mixture the necessary 

 sugars, which are deficient in amount in the legumes. This mixed rape- 

 legume silage may be made in almost any proportion, from 20 parts to 

 80 parts per hundred of rape, and the resulting silage, if properly made, 

 will be pleasant and aromatic in taste and odor, and not too sour. 

 The alfalfa-rape mixture will furnish a silage high in flesh-building and 

 growth-producing constituents, and perhaps better for swine feeding than 

 other mixtures. The following plant materials, however, made successful 

 silage when mixed with rape: corn grain, whole corn plant, potatoes, 

 blue grass, and timothy. 



