34 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



caused by the ration. Evidence on the effect of feeds on the 

 composition of milk should be based on extended feeding trials 

 and not on brief periods of a few weeks, as a temporary effect 

 on the composition of milk of a change of ration n^ay be due 

 to the stimulation of the change in diet regardless of the nature 

 of the change. 



To show that milk fat is not entirely dependent on the fat 

 content of the feed Dr. Jordan and others conducted some ex- 

 perimental work at the New York Geneva Station on this sub- 

 ject, one part of which I shall mention. They fed a cow for 71 

 days on a ration very poor in fat. During that time the cow 

 gave 39 pounds more of fat in her milk than the fat and protein 

 contents of the ration could have furnished, and in addition she 

 gained 15 pounds in live weight. The 39 'pounds more of fat 

 than the fat and the protein of the ration could have supplied 

 must have come directly or indirectly from the carboh3^drates of 

 the ration. 



In bringing out the fact that milk fat production is more or 

 less independent of food fat in the feed I would not have you 

 lose sight of the fact that it has long been known that certain 

 feeds in a ration tend to affect the melting point of the butter fat 

 produced. The writer has observed that a grain ration made up 

 of 50 percent of either oil meal or of soy bean meal when fed to 

 dairy cows produced butterfat which was softer and melted more 

 readily than the butterfat produced by cows fed the regular 

 herd ration. The butterfat produced by cows on green pasture 

 has a lower melting point than that produced by cows on the 

 ordinary winter ration. It is generally recognized that cotton 

 seed meal fed to a dairy cow has a tendency to raise the melting 

 point of the butterfat produced. These facts are interesting, 

 but let us consider the relation of the ration to the percentage 

 composition of the milk produced as far as the solids are con- 

 cerned. 



Extended experiments on the influence of feed on the com- 

 position of milk have been conducted in Denmark, and the results 

 of the work are especially valuable because of the many animals 

 that were included. Woll states that as a result of ten years of 



