MILK PRODUCTION 517 



beyond question by the experiments of Voit, Ktihn and Fleischer, 

 M. Fleisher, Wolff and especially by those of Jordan, 1 while 

 the latter investigator demonstrated that milk fat can be 

 formed from carbohydrates (553). Jordan's experiments on 

 cows, as well as the later ones of Morgen 2 on sheep and goats, 

 likewise show that relatively large amounts of milk may be 

 produced on rations made up of feeding stuffs very poor in fat 

 or from which the larger part of the fat has been extracted. 

 It is scarcely feasible to prepare absolutely fat-free rations for 

 such animals and the writer is not aware of any experiments on 

 milk production with such rations, but it is clear that at most 

 but very small amounts of fat can be regarded as indispensable. 

 612. Addition of fat to rations. Experiments in which the 

 fat content of ordinary rations has been increased, either by 

 the direct addition of fat in one form or another or by the sub- 

 stitution of fat for carbohydrates, have given very contradic- 

 tory results. An increased percentage of fat in the milk has 

 been very frequently observed, sometimes accompanied by an 

 increase in the actual yield of fat and sometimes not, while in 

 other cases the results have been entirely negative. In many 

 instances the experiments are complicated by the fact that the 

 fat was simply added to a basal ration, thus increasing the 

 total amount of feed. 3 The most recent investigations are 

 those undertaken upon a common plan under the auspices of 

 the German Agricultural Council at ten German experiment 

 stations with, in all, 196 cows, the results of which have been 

 reported by Kellner. 4 



The increase in the fat of the rations was effected by the substitu- 

 tion of rice feed 5 for rye meal and starch, so that fat replaced an 

 equivalent amount of carbohydrates. The results, therefore, in- 

 cluded any "specific" effects of these two feeding stuffs, if such there 

 were (618). Per 1000 pounds live weight, the fat-poor rations con- 

 tained 0.25 to 0.50 pound digestible fat and the fat-rich 0.47 to i.io 

 pounds. 



1 N. Y. (Geneva) Expt. Sta., Buls. 132 (1897) and 197 (1901). 



2 Landw. Vers. Stat., 61 (1904), i ; 62 (1905), 251 ; 64 (1906), 93. 



3 Compare Kellner, Die Ernahrung der landw. Nutztiere, 6th Edition, pp. 564-566. 



4 Reichsamt des Innern; fieri chte iiber Landwirtschaft, Heft i and 2. 



5 According to Hansen rice feed has the specific effect of depressing the fat pro- 

 duction, although this effect did not appear manifest in most of these experiments 

 nor in those of Fingerling (613). 



