RAPE AS MATERIAL FOR SILAGE 



By A. R. Lamb, Assistant Chemist, and John M. Evvard, Assistant Chief in Animal 

 Husbandry, Iowa Agricultural Experiment Station 



INTRODUCTION 



The popularity of rape (Brassica napus) as a pasture crop has been 

 steadily increasing since its introduction into this country about 25 years 

 ago. Its value as such is considerable, but its usefulness would be 

 greatly increased if it could be preserved in the silo and used successfully 

 as a succulent feed for the winter months. Attempts to ensile it have, 

 however, evidently been few, perhaps since it has generally been con- 

 sidered too watery for this purpose. The only report of such an attempt 

 which has been found in the literature is from Canada. 1 



In that experiment rape was cut when about 15 inches high and ensiled 

 alone and with an equal weight of corn. When the silage was fed six 

 months later, it was said to have been well preserved, to have had a 

 pleasant odor, and to have been eaten with avidity by cattle. Chemical 

 analyses showed a considerable loss of water and carbohydrates and an 

 increase in nonprotein nitrogen. With the exception of the loss of water, 

 these losses are not much greater than the losses which occur in ensiling 

 the corn plant (Zea mays). In that experiment the total loss of dry 

 matter was 26.5 per cent. Weight for weight, however, rape silage was 

 found by analysis to be a much more valuable feeding material than 

 green rape. 



In 1914, Eward, at the Iowa Station, 2 made rape silage in barrels, with 

 and without the addition of common salt (sodium chlorid). The highly 

 salted silage was quite well preserved and had a favorable odor, but was 

 refused by stock. The unsalted silage contained mold and had under- 

 gone some putrefactive fermentation, the odor of volatile sulphids being 

 quite evident. The shape of the barrels and the consequent difficulty 

 of excluding air on the settling of the ensiled material were responsible for 

 this putrefaction. This emphasizes the importance of using suitable 

 air-tight containers in making rape silage. 



The ideal plant for silage making must contain just sufficient fermen- 

 table sugars to furnish enough acids to preserve it. In most respects the 

 corn plant furnishes the most nearly ideal material for silage. The 

 legumes are not ensiled so successfully because the percentage of protein 

 is too high for the amount of sugar, and some putrefaction is likely to 



1 Schutt, F. T. Report of the chemist. Fodders and feeding stuffs. In Canada Exp. Farms Rpts.. 

 1904, p. 166-182. 1905. 



2 Unpublished data. 



Journal of Agricultural Research, Vol. VI, No. 14 



Dept. of Agriculture, Washington, D. C July 3, 1916 



ed Iowa — 3 



(5 2 7) 



