146 Maine Agricultural Experiment Station. 1917. 



Is this opinion right? Is this curve for changing rate of 

 location due to age, correct in the form impHed by advanced 

 registry rules? 



The purpose of this paper is to answer this question so far 

 as concerns American Jersey cattle seven-day records. It is to 

 ascertain from the data furnished by the seven day milk records 

 in the book "Jersey Sires with their Tested Daughters"" first, 

 the degree of correlation betvv'een age and milk production, sec- 

 ond, the true curve for production at various ages for the seven 

 day records of the Jersey breed, and then third, from these fig- 

 ures to determine the age correction for the seven day records 

 so that they may be reduced to a common basis for comparison 

 in future studies of the inheritance of milk production in the 

 Jersey breed. 



The character of the statistics in this volume — "Jersey Sires 

 with their Tested Daughters"- — is varied. About 90 per cent of 

 them are taken from the private records of the earlier Jersey 

 breeders, and 10 per cent are authenticated ; that is each one of 

 these latter was supervised by a representative from the office 

 of the American Jersey Cattle Club, or by one from the office of 

 the Agriciiltural Experiment Station in the State in which the 

 test was performed in the same way that Advanced Registry 

 tests are supervised today. 



Though unauthenticated there is every reason to believe 

 that the milk reports are true accounts of actual production, 

 because butter was the part of fhe milk which the breeders 

 wished to produce. To obtain this butter fat content of the milk 

 it had to be skimmed and the cream churned as at that time the 

 Babcock Test was not in general use. Consequently if there 

 was any fraudulent work done, the incentive for it was in the 

 making of the butter and not in the weighing of the milk pro- 

 duced. This idea is substantiated by the fact that no abnormally 

 high averages of milk production for the different ages appear 

 upon analysis of the records. 



All the seven day tests in the volume cited, for which milk 

 records were given, were the ones on which this paper is based, 

 the total number used being 5821. 



"'Jersey Sires and their Tested Daughters". Published by American 

 Jersey Cattle Club, New York, 1909. 



