80 ~ Report oF THE DigkcotToR OF THE 
When a difference is to be seen in the number of* days given 
in this and the following table from those given in tables relating 
to cost of milk and fat, it is due to the fact that, toward the close 
of the period, the milk yield was very slight and was taken but 
once aday. In these cases, in tables like the above, it is obvi- 
ously unfair to reckon all the days in which milk was given. 
For this reason, also, the sum of the morning’s and evening’s 
milk, as given in the following table, for any particular cow for 
any given period, will not always equal the total amount given 
in tables Atanas to milk and fat. 
Table 70 gives the relation of fat in food to fat in milk for 
each animal in her first period of_lactation. Pure fat estimated 
at 82.6 per cent. of ether extract in this and following tables. 
Table 71 gives the relation of fat in food to fat in milk for 
each animal in her second period of lactation. 
Table 72 gives the relation of fat in food to fat in milk for 
each animal in her thzrd period of lactation. 
Table 73 gives the relation of fat in food to fat in milk for 
each animal in her fourth period of lactation. 
Table 74 gives certain general results as to food and production 
of each cow during her jirst period of lactation. 
Tables 75, 76 and 77 give the same general results as to food 
and production of each cow during the second, third and fourth 
periods of lactation. 
