36 RfiroRT OF Department of Animal Husbandry of the 



METHODS OF SAMPLING AND ANALYSIS. 



The rations were weighed out at several different times during 

 the course of the experiment, and each time this was done 

 samples were taken of the various foods. 



The milk, urine and feces were taken directly to the labora- 

 tory and immediately weighed and sampled, excepting that the 

 night's milk was kept in an ice box until morning, when it was 

 mixed with the morning's milk and a sample was then drawn 

 from the mixture. The feces were thoroughly stirred and 

 samples (4 lbs.) of the fresh material were taken for drying. 

 These samples were dried over steam coils at a temperature 

 ture not exceeding 60° C. 



In general the methods of the A. O. A. C. were followed in 

 the analyses, the only exception being that petroleum ether was 

 used instead of sulphuric ether in extracting the fats from the 

 foods and feces. (See Bulletin 132.) 



Nitrogen was determined directly in fresh samples of the 

 urine and feces. The drying of the feces at a temperature vary- 

 ing from 50° to 60° C. caused a material loss of nitrogen, as 

 previous results clearly show. (See Bulletin 132.) 



THE RESULTS OF THE EXrEEIMENTS. 



The results of these experiments are presented without a full 

 statement of the data involved. 



The omissions are the daily weights and daily composition of 

 the feces, urine and milk, the figures for which would occupy 

 many pages and would be of use only to those who wish to 

 study the data from some standpoint not considered by the 

 authors. 



The points that will be discussed are the following: 



(1) The digestibility of the rations, with some reference to 

 the influence upon digestibility of the proportions of nutrients 

 in the case of Cow 12. 



(2) The influence of the composition of the ration upon the 

 quantity and composition of the milk and upon the composition 

 of the milk fat. 



