4 MASS. EXPERIMENT STATION BULLETIN 425 



Since grasses and legumes at the proper stage for ensiling contain more than 

 70 percent and sometimes as much as 80 percent of moisture, it follows that some 

 wilting is almost always necessary when a preservative is not used. Some sort 

 of equipment for determining the approximate amount of moisture in a wilted 

 crop is therefore essential, especially for the novice. There is on the market at 

 least one such device but its cost is high unless shared by several farmers. Less 

 accurate but probably a sufficient guide is a homemade device recommended by 

 the Bureau of Dairy Industry, United States Department of Agriculture. This 

 can be made from materials available on most farms by anyone possessed of a 

 little mechanical aptitude. Plans for it are given on the last page of this bulletin, 

 also a table showing how to interpret results from its use. 



Preservatives Investigated 



Where for any reason wilting is not practicable, as for example in the operation 

 of field choppers, some sort of preservative is essential to the production of good 

 quality grass silage. The one exception is silage made from the small grains, 

 especially if the grain has reached the dough stage. Numerous substances have 

 been used as preservatives, and most of them have been investigated by this 

 station. For the most part they fall into one of two categories: (1) those in 

 which the acid needed to prevent spoilage is added directly, and (2) those which 

 contain sugar or other readily fermentable carbohydrate, in which case the needed 

 acid is a by-product of the silage fermentation. 



Typical of the first class is phosphoric acid. Since wartime demands have 

 pre-empted most of the production of phosphoric acid for more essential uses, 

 not so much is heard about this acid as a silage preservative. It was given a 

 three-year trial at this station in 1938-40. Although it was easy to apply and 

 did a good job of preservation, the silage was not very palatable, being quite 

 inferior in this respect to the silage produced with certain other preservatives. 



Molasses has been the most frequently used of preservatives in the second 

 class. Although there have been some failures with it, experience leads to the belief 

 that they have been due to use of an insufficient amount. In general, when 

 properly distributed in adequate amounts, molasses produces a sweet-smelling, 

 palatable silage. Its disadvantages are that it is a bit messy, and oftentimes will 

 not flow fast enough to keep pace with the chopping capacity of a cutter, thus 

 necessitating dilution with water which means considerable extra labor. The 

 minimum amount of molasses recommended is 60 pounds per ton of green crop; 

 more recent experience has demonstrated that the 40 pound minimum recom- 

 mended in the earlier bulletin is too low. 



Under conditions prevalent since 1942 molasses has become relatively high 

 priced and hard to obtain; the natural result has been a search for substitutes. 

 Most success has been attained with some sort of ground grain; all of the cereal 

 grains have been used. The action of such material apparently is two-fold. 

 Besides furnishing an abundance of readily fermentable carbohydrate, the 

 ground grain soaks up much of the excess moisture from the green crop, and the 

 result is a moisture content in the whole mass of silage more nearly optimum for 

 best results, not to mention reduction of objectionable seepage. For example, 

 the addition of 150 pounds of ground grain with a moisture content of 10 percent 

 to a ton of green crop containing 75 percent moisture will reduce the moisture 

 content of the total mass to just about 70 percent. 



