July 3, 1916 Rape as Material for Silage 531 



The jars were opened four months after filling and the condition, 

 appearance, odor, and taste of the silage noted. (See Table I.) With 

 very few exceptions it was in a perfect state of preservation, of excellent 

 texture and color, with a pleasant, somewhat aromatic odor, and gen- 

 erally of an agreeable taste, though quite sour. It was succulent with- 

 out being too moist, even though it had been made in a tightly sealed 

 jar, with almost no opportunity for the evaporation of water. In order to 

 ascertain its palatability to swine, a representative number of the various 

 mixtures and some of the pure rape silage were fed to three lots of pigs. 

 At first the animals, which were on a ration consisting mainly of corn 

 and tankage, tasted the silage rather hesitatingly and seemed surprised 

 by the sourness, but kept at it until they had eaten it all, appearing to 

 enjoy its succulency. On a second trial, three days later, the same ani- 

 mals ate it with great relish. Only one sample of those tried, a rape- 

 molasses mixture, was refused by the animals. In nearly every case 

 after eating this silage they went to the corn self-feeders. xVn extensive 

 feeding experiment to determine the effect of feeding rape silage upon 

 the growth and well-being of swine is contemplated. 



CHEMICAL EXAMINATION OF SILAGE SAMPLES 



The data from the chemical examination of the samples are shown in 

 Table I. The juice was pressed out from the silage, and samples were 

 taken from the juice with pipettes. This method has been used with 

 corn silage and is a quite accurate and excellent comparative method 

 for quickly determining the character of a sample of silage. Estimations 

 of the total acidity and moisture content were made on all samples, and 

 estimations of volatile acidity, alcohol, and amino nitrogen on a few 

 representative samples, according to the following methods. (See 

 Table I.) 



Total acidity. — Ten c. c. of juice were diluted to about 500 c. c. with carbon- 

 dioxid-(C0 2 )-free water, and titrated with decinormal barium-hydroxid solution in 

 the presence of phenolphthalein till a distinct pink appeared by reflected light against 

 a white background. 



Vol atilE acidity. — Fifty c. c. of juice were diluted to 100 c. c. with carbon-dioxid-free 

 water and distilled with a current of carbon-dioxid-free steam. To hasten the libera- 

 tion of volatile acids and alcohols, 100 gm. of sodium chlorid were added to the juice. 

 About 500 c. c. of distillate were titrated with baryta water in the presence of 

 phenolphthalein. 



Alcohol.— Distillation method: The distillate from the volatile-acid determination 

 was neutralized with baryta water (solid phenolphthalein being added) and concen- 

 trated by repeated distillation with sodium chlorid. 1 



About 50 c. c. of alcohol solution were oxidized 2 in a pressure flask in a boiling 

 water bath for 30 to 40 minutes, and the volatile acids then distilled off four or five 



1 Bacon, R. F. Detection and determination of small quantities of ethyl and methyl alcohol and of 

 formic acid. U. S. Dept. Agr. Bur. Chem. Circ. 74, 8 p. 1911. 



2 The oxidizing solution used was made up in the following proportions: 10 gm. K2Cr207, 20 gm. H2SO4. 

 70 gm. water. 



42717°— 16 2 



