522 NUTRITION OF FARM ANIMALS 



Whether such relatively large losses by fresh cows usually 

 accompany copious milk production and are made up again in 

 the later stages of lactation, and whether this depletion of the 

 mineral reserves of the body is one of the factors in the natural 

 shrinkage of milk production, as suggested by Forbes, are 

 matters for future investigation. 



It is evident, however, that none of the foregoing data afford 

 much information regarding the real ash requirements of dairy 

 cows. 



Feed as a stimulus to milk production 



617. Flavoring substances. By flavoring substances is 

 meant those whose presence in small amounts improves the 

 odor or taste of a feeding stuff or ration while not adding ma- 

 terially to its content of protein or energy. In other words, they 

 are substances which do not yield matter or energy to the body 

 in the ordinary sense, but which may nevertheless affect the 

 course or rapidity of metabolism. 



That the flavor or aroma of feeding stuffs is not an insignif- 

 icant element in determining their commercial value, not only 

 for milk production but for other purposes, is well established 

 by practical experience. This superiority is doubtless due 

 largely to the fact that a palatable feed is consumed more freely 

 than one lacking in flavor. In the case of milk production, 

 however, it appears that, within certain rather narrow limits, 

 various flavoring materials may act as a direct stimulus to the 

 milk gland, causing a greater yield of milk and especially of fat. 



In Morgen's experiments on milk production cited on previous 

 pages extensive use was made of rations consisting largely of 

 almost flavorless materials. With such rations it was found 

 to be impossible to secure yields equal to those obtained from 

 rations supplying equal amounts of protein and energy but 

 made up of normal feeds. The addition to these flavorless 

 rations, however, of such substances as fennel, anise or hay 

 distillate, or the introduction of malt sprouts, caused a distinct 

 increase in the milk yield, so that, with rations containing a 

 sufficiency of fat, almost or quite normal results were secured. 1 

 Moreover, a distinct effect was observed in increasing the fat 

 production and the percentage of fat in the milk. 



1 Landw. Vers. Stat., 61 (1904), i- 



