N. H. Agricultural Experiment Station 



4- G S lO 



AGE AT FRESHENING 



2 14 



N YEARS 



Figure 2, Index of dairy cow production according to age at time 



freshening (1926=100). 



of 



first and second calf heifers. These men would be producing somewhat 

 less milk and at greater cost per unit (not including appreciation) un- 

 der this management, but by selling cows at the period of greatest value 

 may have a greater net under their conditions. 



The men who purchase cows at this period of greatest value are con- 

 fronted with the reverse situation of depreciation each year. How- 

 ever, if the milk from these cows commands a high price, the cost of 

 depreciation may be relatively unimportant. 



Since, in general, production declines after the seventh year, there 

 is a tendency to discard the lower group of producers in each age class 

 each year. In a group of 2535 cows in D. H. I. A. of known ages, less 

 than three per cent of the cows had freshened after the eleventh year, 

 and only about eight per cent after the ninth year. 



This culling process is intimately related to the problem of replace- 

 ments because the heavier the culling the larger the number of replace- 

 ments. The cost of replacements, the depreciation to be expected, and 

 the price of milk are important factors to be considered in making de- 

 cisions as to culling. 



The value of the cow for slaughter is declining from about the fourtli 

 year on, and when beef is high the change in beef value each year is an 

 important part of the depreciation costs. At such times the spread be- 

 tween replacement value and value of the old cow for beef may be large. 



Management in the individual herd has an important bearing on 

 culling. Good sound cows well cared for and not forced are likely to 

 remain in production longer. On the other hand, the frequent pur- 

 chase of inferior stock, presence of disease, and poor handling may use 

 up cows to such an extent that replacement is a very large item in the 

 costs of milk production. 



