32 Milk and Its Products 
on the percentage of fat in the milk. In the one 
ease 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 
B-year-olds .... 81 3.31 25 » Sa 
4-year-olds.. 59 3.41 18 3.68 
5-year-olds oe 37 3.42 12 3.60 
6-year-olds 36 3.34 8 3.49 
T-year-olds . . 22 3.25 5 3.68 
8-year-olds 14 3.40 
9-year-olds 10 3.37 ‘ 3.80 
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: 
