22 



HATCH EXPERIMENT STATION. 



[Jan. 



Butter Fat Analyses. 

 First 2^eriod : both herds normal oil ration. 



The averages show that the effect of the oil was to depress 

 the vohitile acids and to increase the melting point and iodine 

 number. The change was noted in the case of Herd II. at 

 the beginning of the excess oil period, and continued unin- 

 terrupted until its close. 



In the third period of two weeks (one week preliminary 

 and two weeks proper), in which both herds received the 

 normal oil ration, the butter fat in case of Herd II. changed 

 in composition nearly to that of Herd I. at the close of the 

 second i)eriod. The effect of the change of feed was observed 

 at the close of the first week, but it seemed to require several 

 weeks for the animals to thoroughly readjust themselves. It 

 is evident that the linseed oil caused a butter fat to be pro- 

 duced having lower volatile acids than that produced in the 

 normal oil period. One would also assume that it caused a 

 change in the relative proportions of stearin, palmitin and 

 olein. The question arose as to whether linolic and linolinic 

 acids — the characteristic acids of linseed oil — had been 

 actually transmitted to the butter fat, and an effort was made 

 to detect them, but without positive results. We hope to 

 still further investigate this matter. 



