ment, home-grown replacements can be grown to the correct size for breed- 

 ing at an earlier age. Proponents of raising replacements on the farm also 

 advance the argument that the productive life span is longer for raised 

 replacements, and that raised cows produce more milk than purchased cows. 



Most farms present a dynamic adjustment picture. Adjustments in 

 both size of operation and production practices are continually taking place. 

 Thus in observing actual practices on a fann, it is difficult to decide what 

 part of the change in net farm income is due to the adoption of a certain 

 practice and what part is due to a change in size of business that often 

 accompanies changes in practices or management. Farm budgets, however, 

 permit testing the effect on income of changes in farm organization or 

 practices with the same quantity of farm resources. In other words, it is 

 possible to estimate the net effect of a proposed change in organization 

 independently of a change in size of business. 



In this appraisal of the net effect of various types of replacement 

 practices, the several farms considered differ as to proportions of resources 

 and with respect to location in the milkshed, but the individual farm re- 

 sources were assumed to remain unchanged. The system of obtaining re- 

 placements was varied from raising all replacements, to raising some and 

 buying some, and to buying all of them. Thus the true net effect of the 

 changes in management on income from each of the farms was obtained. 



Sources of Information for Appraisal of 

 Replacement Problem 



A FARM survey and records from the New Hampshire Dairy Herd Improve- 

 ment Associations were the major sources of information for the study. 

 The survey included 62 dairy farms that differed with respect to location 

 in the Boston milkshed and size of herd. The types of information that 

 were obtained consisted of the farmer's attitude toward purchased replace- 

 ments, numbers of livestock, disease control and prevention practices, 

 supply of forage, barn facilities, and labor force. The New Hampshire 

 Dairy Herd Improvement Association records provided information on herd 

 life, age at disposal, reasons for disposal, production of milk, and age com- 

 position of cows in a large number of herds. Data from each source were 

 used throughout the study wherever applicable. 



The major kinds of data assembled and analyzed were as follows: 



(1) Feeding rates for cows and young stock. 



(2) Milk production rates for raised and purchased cows. 



(3) Mortality and culling rates for young stock. 



(4) Incidence of disease, years in herd, age at disposal, and 

 life expectancy for raised and purchased cows. 



(5) Yields for hay, silage, and pasture. 



(6) Chore work for cows and young stock. 



(7) Available barn space and utilization by cows and young stock. 



(8) Flexibility and limitations in use of resources for either cows 

 or young stock. 



(9) Prices for products sold and purchased. 



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