150 



DAIRY CATTLE AND MILK PRODUCTION 



to have heifers drop their first calf when from 24 to 27 months 

 of age, so "Lactation Period No. 1 " as given in the table 

 is the two-year-old record. 



The " lactation period " as used here is the entire milking 

 period, if it be less than 12 months ; if the milking period ex- 

 tended beyond a year, the figures used are for the first 12 

 months only. The amount of milk is the total from weights 

 taken of each milking separately. The per cent of fat was 

 taken each month from a composite sample covering ten milk- 

 ings in the middle of the month. 



In Table 7 the records are first given of the yield of milk 

 and per cent of fat by lactation periods for 41 cows, of which 

 records are at hand for the first three milking periods. Then 

 follow the records of 28 cows for the first four periods, 21 

 cows for five periods, etc. 



Table 8 gives the data for the Jersey herd, regarding the 

 fat yield in another form. Here the highest yield of fat is 



TABLE 8 

 JERSEY HERD 



UNIVERSITY OF MISSOURI 



FAT PRODUCTION BY YEARS EXPRESSED IN PER CENT 



