Food Requirements for Milk Production 311 



which is now regarded as too small when both food 

 ecouomj- and the efficiency of the ration are considered. 

 With this amount of protein in sixteen pounds of total 

 digestible matter, the nutritive ratio of the ration would 

 be about 1:9.5. A ration with as wide a ratio as this 

 is regarded by the great majority of careful experi- 

 menters, and most intelligent dairymen, as less efficient 

 than one richer in protein. While it is not possible 

 to point out just how more protein is used, there is no 

 question but that a larger quantity promotes the flow 

 of milk. Few instances are on record where, in care- 

 fully conducted experiment station work, other condi- 

 tions being the same, a moderate ration with a nutritive 

 ratio of 1:5.5 to 1:6.5 has not proved to be more 

 efficient than one equivalent in quantity but with a 

 ratio materially wider. The observations of Atwater 

 and Woods among the dair\' herds of Connecticut, 

 where the owners were induced to narrow the rations 

 they were found to be using, gave emphatic testimony 

 as to the desirability of a larger proportion of protein 

 than is ordinarily supplied in a home-grown ration. 

 This added protein may not be needed for construction 

 uses, but its presence certainly in some way induces 

 an increased milk secretion. The chemical changes 

 involved in milk formation are obscure and complex, 

 and it may be that this extra protein somehow enters 

 into these transformations. One view which appears 

 to be rational is that the presence of a generous amount 

 of circulatory protein stimulates the cells of the body 

 to great metabolic activity, thus promoting the secretion 

 of milk solids. 



