330 THE FEEDING OF ANIMALS 



433. Standards for milk production based on 

 elaborate American feeding experiments. Three in- 

 vestigators, Haecker, Savage, and Eckles, carried on 

 extensive semi-practical experiments for the purpose of 

 determining the relation between the food of a cow and 

 her milk production. These several studies were inaugu- 

 rated for practically the same purposes, viz., to deter- 

 mine protein demand for milk production and the neces- 

 sary quantities of total digestible nutrients. More- 

 over, the data secured have been applied differently 

 from those derived from previous similar experimental 

 work. The final measurements have been based, not 

 wholly upon the weight of the animal or upon total milk 

 production, but also upon the protein and total nutrients 

 necessary for the production of one pound of milk with a 

 given percentage of fat. It is on this basis that these three 

 pieces of experimental work may be compared. 



Haecker began his records in 1892 and carried them 

 through, during definite periods, until 1901. The experi- 

 ments upon which his final conclusions are principally 

 based were carried on in 1894-1895 for a period of 154 

 days, and in 1900-1901 for a period of 113 days, the num- 

 ber of cows involved in the first period being 12 and in 

 the last period 20. The fodders were analyzed only in 

 part, and the digestibility of the various feeding-stuffs 

 was calculated on the basis of average digestion coefficients, 

 with due reference to the condition of the coarse fodders. 



Savage's work was done from 1909 to 1911. In both 

 experiments twelve cows were used in three feeding 

 periods of six weeks each, production records being kept 

 for five weeks in each period. The fodders were analyzed 

 but their digestibility was calculated from average diges- 

 tion coefficients. 



