QUANTITY 143 



lactation period, and, so, time can be gained and the 

 effects of disturbing causes eliminated. The inspection 

 of a large number of records showed that the daily 

 yield rises to a maximum which is reached a few weeks 

 after calving, and, if this maximum, as found on a 

 smoothed-out yield-curve, be multiplied by 200 in 

 the case of a cow calving in the middle of winter and 

 by about 180 in that of another calving in the middle 



OWEEKSIO 



20 



30 



40 



50 



of summer, the normal yield for the lactation will be 

 given. This result was also confirmed by Mr. Gavin, 

 who found that what he called the " revised maximum " 

 yield, that is the lowest yield maintained for three 

 successive days when the cow is at her maximum — in 

 the three cases, 50, 50, 50 ; 50, 54, 50 ; and 50, 52, 54 ; 

 50 is the revised maximum — should be multiplied by 

 195 for winter-calved cows and 187 for summer. 



The above diagram consists of the smoothed-out 

 curves of the daily yields of cows giving 1000, 750, and 

 500 gallons a year. 



