June 17, 1918 Physical Changes in Feed Residues iri Cattle 



641 



Table II. — Summary of tests made in igi6 



Method of making physical analysis. — A quantity of each lot of 

 residues of which an analysis was to be made was placed in a 1,200-c. c. 

 shaking flask, after which distilled water was added to make up to 400 c. c. 

 This was then shaken in a machine operated by motor for two hours at 

 room temperature. The contents were placed on a brass screen with 

 2 -mm. round holes; the mixing flask was cleansed, and the residue 

 washed on the screen with 100 c. c. of distilled water.^ The residue was 

 removed from the screen to a mortar containing 50 c. c. of water and 

 was ground very lightly; after this it was placed on the screen, 50 c. c. of 

 water being used to clean the mortar. The whole was washed again 

 with 100 c. c. of water, the process being repeated until the residue was 

 apparently free from true feces or the finely divided particles. The 

 corn-silage residue, the part left on the screen and designated as fraction 

 "a" was then transferred to filter paper, dried, and weighed. 



After fraction a had been removed, the filtrate washings were treated 

 with 3 gms. of potassium aluminium sulphate, [K2SO4.AI3 (804)3. 24 HjO], 

 placed in a mixing flask, made up to 1,000 c. c. with distilled water, 

 shaken at room temperature for one hour, and allowed to stand a few 

 minutes to permit partial sedimentation. It was then filtered by decan- 

 tation and washed with distilled water until free from sulphates. The 

 residue constituted fraction b. The filtrate with washings constituted 

 fraction c, which for this study was not considered. After the separation 

 had been completed, fractions a and b were dried in an oven at 105° C. 

 to constant weight. 



DISCUSSION OF RESULTS 



The data presented in Table III provide material for making studies 

 on the physical changes in feed that take place during the digestion of 

 coarse feeds in cattle. This is especially true of the first two tests, in 

 which silage alone was fed, to a lesser extent in case of the next two 

 rations containing both silage and cottonseed meal, while for certain 

 phases of this study the last two rations can not be considered, since the 



• Distilled water was used for all purposes in making the separation. 



