Refinement of Feeding Experiments for Milk Production 243" 



TABLE 20. Relation of Age to Milk Production 



(Averages of 60 cows for 5 lactations) 



TABLE 21. Relation of Age to Milk Production 

 (Averages of 40 cows for 6 lactations) 



TABLE 22. Relation of Age to Milk Production 

 (Averages of 26 cows for 7 lactations) 



Lactation 



Milk 



production 



(pounds) 



Number 

 of days 

 milked 



Number 



of days 



dry 



Per cent 

 of pro- 

 duction 

 for seventh 

 lactation 



I 



2 

 3 

 4 

 5 

 6 



7 



7,376.6 

 7,383.6 



9,3677 

 9,027.6 

 9,432.2 



9,034-4 

 10, 127.0 



346 

 297 



331 

 314 

 316 



315 

 330 



53 

 55 

 53 

 54 

 53 

 73 

 62 



73 

 73 

 92 

 89 



93 



89 



100 



35.3 



