THE EFFECT OF FEEDING FAT ON THE FAT 

 CONTENT OF THE MILK. 



J. M. Bartlett. 



The preceding experiments were not undertaken to test the 

 effect of the fat of the food on the yield of fat in the milk. In 

 the first two experiments (see pages 99 to 105) the feeding periods 

 were not long enough and the milk was not tested often enough 

 to give reliable data on this point. In experiment III, (see 

 pages 105 to 108) however, the feeding periods were longer, 

 being for the most part 28 days. A composite sample of the 

 milk of each cow taken during the last four days of each week 

 was tested and had it not been for the misfortune of having part 

 of the records of the milk yield destroyed, we would have had 

 considerable reliable data bearing on the subject. A number of 

 attempts have been made in this country, also in Europe, to feed 

 fat into milk, but with a few exceptions the experimenters have 

 arrived at the same conclusion, viz., that the per cent of fat in 

 the milk depends on the individuality of the cow, and can only 

 be slightly or temporarily varied by the food. 



Prof. Soxhlet * in 1896 made some experiments in which he 

 claims to have materially increased the fat in milk of cows by 

 feeding them oil in the form of an emulsion. The oil was emul- 

 sified for the purpose of aiding the animals in digesting it. The 

 author believes others have failed to get like results for the rea- 

 son that the fats have not been fed in digestible forms. He 

 gives very little data as to the details of his experiment and most 

 of the paper is given up to theorizing and discussing the results. 

 In the discussion mention is made of feeding periods of four and 

 eight days, and no further mention of time is made. If such 

 short feeding periods were employed, the results can easily be 

 explained, as nearly every one who has experimented with cows 

 has had like experiences. 



* Experiment Station Record (Vol. 8, pp. 1016). 



