1902.] 



PUBLIC DOCUMENT — Xo. 33. 



33 



Field G. — Varieties of Ensilage Corn, Food Substance per Acre 



(^Pounds). 



Examination of the tabic shows that the variety giving the 

 heaviest yield (green weight) also furnishes the greatest 

 number of pounds total dry matter ; but when we compare 

 the figures of the other columns in the table, it will be seen 

 that this excess of dry matter is made up entirely of fibre 

 and nitrogen-free extract, which are the least valuable con- 

 stituents. In total yield of protein (the most valuable con- 

 stituent) the Eureka is exceeded by two varieties, — Learning 

 Field and Rural Thoroughbred ; in yield of fat it is much 

 exceeded by the Leaming Field. It would seem the last- 

 named variety, though giving the smallest yield, should be 

 preferred. One pound of digestible fat is commonly con- 

 sidered to have a food value equal to two and one-half pounds 

 of digestible fibre, or extract matter. Fat is commonly 

 equally as digestible as nitrogen-free extract, and is less 

 afl'ccted by the fermentations which go on in the silo than 

 are the starches and sugar (extract matter). It is more 

 digestible than fibre. In corn which is approaching maturity 

 the proportion of starch is comparativcl}' high ; this food 

 substance is at that time abundantly stored in the grain. 

 As corn approaches maturity, while the starch increases, 

 the proportion of sugar in the juice of the plant decreases. 

 Sugtir in green corn fodder is a valuable food substance, but 

 in the silo the sugar is largely converted into acid, and acid 

 has no food value. Starch, while it may suffer some loss in 

 the silo, is far less aflt!cted than is sugar. Other things 

 being equal, the imniatur(! corn will make, under average 

 silo conditions, a more acid silage than corn which is nearer 

 ripe. Tlu; large proportion of water in inunature corn, as 

 well as the relatively large amount of sugar, favor de\'elop- 



