12 MASS. EXPERIMENT STATION BULLETIN 362 



legume silages are higher in protein, fiber, and minerals and lower in carbohydrates 

 than corn silage. This statement, coupled with the figures in the table, throws 

 further light on the fundamental reason why corn makes good silage without the 

 addition of any preservative (see page 2). There was a great variation in carotene 

 content of these materials, due partly to such external causes as stage of maturity 

 at harvesting, and packing in the silo. 



Consider for instance the second sample in the table, which had the lowest 

 carotene content of the lot. It had also the lowest content of minerals and the 

 highest content of fiber, a combination of factors which indicates that the tim- 

 othy from which it was made was either very coarse or too mature when harvested, 

 perhaps both. Superficial examination of the sample when received, showed it to 

 be rather stemmy with small spots of mold distributed all through it. Such a 

 condition suggests material too mature to pack well in the silo, leaving tiny air 

 spaces with consequent development of mold and destruction of carotene. 



Acidity of Grass and Legume Silages 



Several inquiries have been made as to the degree of acidity in this type of 

 silage, and v/hether it is higher or lower than in corn silage. Determinations were 

 made during the winter of 1937-38 with the following results: 



pH Active Acidity 



(Hydrogen ions per million 

 of silage) 



Grass silage 3.75 178 



Alfalfa silage 4 . 20 63 



Corn silage . 3 . 68 209 



Since low pH readings mean high acidity and vice versa, the figures mean that 

 the corn silage was more acid than either of the other two. In terms of active 

 acidity, corn silage was somewhat stronger than the grass silage and more than 

 three times as strong as the alfalfa silage. A range between pH 3 and pH 4 is 

 generally considered satisfactory for silage. Below pH 3, the material is probably 

 too acid to be fed continuously to cattle. Above pH 4, the chances of spoilage 

 due to growth of molds are greatly increased. 



Temperatures Reached in the Silo 



On page 2 elimination of the fire hazard was given as one of the advantages 

 of ensiling grasses and legumes. In this connection, it is of interest to note that 

 the highest temperature recorded by a pyrometer connected to a thermocuple, 

 buried at about the center of the silo, was 93° Fahrenheit. This is in agreement 

 with work done at the New Jersey Experiment Station, which reports tempera- 

 tures seldom going above 100° Fahrenheit, provided the grass was not allowed 

 to dry out to any e.xtent before chopping. Temperatures in hay mows may run 

 as high as 160° F., and where spontaneous combustion occurs, of course, they are 

 very much higher. 



Feeding Practice 



The ensiled crop may be fed out at once, but it will keep better from day to 

 day in the silo if first allowed to go through the fermentation process, which 



