MILK PRODUCTION ,'. 529 



in considering that question, both the planning and execution 

 of many of the older experiments were defective and their 

 results must be regarded as inconclusive. The more recent 

 experiments of Hansen and of the German Agricultural Coun- 

 cil, on the other hand, as well as the investigations of Morgen, 

 Fingerling and their associates upon the influence of feed fat 

 and of condiments upon milk production, afford numerous ap- 

 parently unquestionable instances of an effect of the ration 

 upon the fat content of the milk. 



For example, the experiments of the German Agricultural 

 Council on palmnut meal (620) showed an average increase in 

 the percentage of fat ranging in the different experiments from 

 4 per cent to n per cent, while individual cows showed even 

 more striking differences. Morgen's results on the specific 

 effect of feed fat when added to fat-poor rations (613) and like- 

 wise Fingerling 's results regarding the influence of condiments 

 (617) afford even more striking examples of the same effect. 

 Apparently it must be admitted that, under some conditions, 

 the fat content of milk may be distinctly affected by the feeding 

 and that this effect appears to be associated with the fat supply 

 of the ration. 



625. Influence on percentage of fat in solids. Further- 

 more, it appears from such of these latter experiments as in- 

 cluded determinations of the total solids of the milk that the 

 increase in fat content was essentially a " one-sided " increase, 

 i.e., that the proportion of fat to other solids in the milk was in- 

 creased. This was notably the case in the majority of experi- 

 ments on fat-poor rations, in which the proportion of fat in the 

 milk solids was increased by from 12.5 per cent to 23.5 per cent 

 by the addition of fat to the feed. Similar although much less 

 marked results were also obtained in Fingerling's experiments 

 upon the influence of condiments. 



In Hansen's experiments, too, the influence on the fat content 

 of the milk was due, in the majority of instances, largely to an 

 increase or decrease of the percentage of fat contained in the 

 milk solids, the increase or decrease over the comparison rations 

 being over 5 per cent in fully one-third of the experiments, 

 while Lindsey l has confirmed Hansen's results as regards 

 cocoa meal. 



1 Mass. Expt. Sta., Bui. 155. 

 2 M 



