MILK PRODUCTION 325 



In general, small cows eat proportionately more food than 

 larger ones. 



424. Protein requirements for milk production. The 

 question now arises, What proportion of this quantity 

 should be protein? The actual amount of proteins in 30 

 pounds of average milk, for instance, is about 1 pound. 

 If .70 pound is needed daily for mere maintenance then 

 1.7 pounds of protein must be used for maintenance and 

 milk formation, a quantity which is now regarded as too 

 small to sustain such milk production when both food 

 economy and the efficiency of the ration are considered. 

 With this amount of protein in 16 pounds of total digesti- 

 ble matter, the nutritive ratio of the ration would be 

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

 be regarded by the great majority of careful experiment- 

 ers, and most intelligent dairymen, as less efficient than 

 one richer in protein. Few instances are on record where, 

 in carefully conducted experiment-station work, other 

 conditions 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 dairy 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 

 usually supplied in the ordinary home-grown ration. 



There are several possible reasons why the protein 

 requirement of a non-productive animal plus the protein 

 found in the milk does not constitute a proper standard 

 for a milk ration: 



1. The stimulating effect of a generous supply of pro- 

 tein upon metabolic activity. 



