32 Milk and Its Products 



on the percentage of fat in the milk. IE the one 

 case the observations were made upon a large num- 

 ber of cows of all ages, for a week at a time, com- 

 paratively early in the period of lactation. In the 

 other the observations were made upon a single herd 

 extending over several years, and the percentages of 

 fat are the average for the whole period of lactation 

 The percentages of fat for the different ages are as 

 follows : 



" Official " weekly tests of Observations on Cornell 



Holstein-Friesian cows. University herd, 1891-8. 



No. Average No. Average 



of Cows, per cent fat. of Cows, per cent fat. 



2-year-olds 147 3.29 25 3.71 



3-year-olds 81 3.31 25 3.71 



4-year-olds . . . . 59 3.41 18 3.68 



5-year-olds 37 3.42 12 3.60 



6-year-olds 36 3.34 8 3.49 



7-year-olds 22 3.25 5 3.68 



8-year-olds . . . \ 14 3.40 \ 



9-year-olds .... 10 3.37 J * 



10-year-olds 9 3.83 



11- and 12-year-olds - 4 3.57 



The breed of the cow also influences very largely 

 the percentage of fat in the milk. Cows of certain 

 breeds normally give milk much richer in fat than 

 others. 



The following, compiled from a large number 

 of analyses made at various American Agricultural 

 Experiment Stations, will give a general idea of 

 the average composition of the milk of the more 

 common breeds, so far as it relates to total solids 

 and fat: 



