654 ON INBREEDING IN JERSEY CATTLE. 



Table III. 

 Further Correlation Coefficients of Related Cows. 



Further, Pearl, Gowen and Miner (1919) in their work on the American Jersey, 

 give a list of sires in order of their sons' performances as parents of productive heifers. 

 While certain bulls came out of this study to their credit, there are what the authors 

 call ' certain disappointments.' The greatest of these are the sons of Hood Farm 

 Torono 60326, who, without exception, lowered the production of their daughters. 

 Hood Farm Torono clearly led amongst the list of sires in increasing the milk production 

 of his progeny over that of their dam. There are also other such ' disappointments.' 

 The sons of imported bulls make a rather better showing, but here again there are 

 similar cases, the male progeny of Noble of Oakland being one of them. 



Gowen (1925), working with the Guernsey breed, shows how great is the variation 

 in the yields between the sire's daughters and his son's daughters. He states, ' Thus 

 we could expect from any given grade of sire, whether his daughters were high or 

 low, sons which would have daughters ranging from the highest to the lowest producers 

 in the breed.' Again ' The variation of the sons' daughters in production is also 

 practically the same as that of the whole breed.' The point to be gathered from this 

 work is that, while the sons tend to revert to the average of the breed, this is not 

 nearly so marked in the daughters. Thus further evidence is obtained in favour of 

 the hypothesis that one or more of the factors governing milk production, both yield 

 and butter fat percentage, are inherited in a sex linked manner. 



This is partly hypothesis, and while the premises on which it is based are exceedingly 

 suggestive they cannot yet be taken as absolutely sound. No valid grounds have 

 been found upon which to disprove it, but the matter requires further investigation 

 because, if the hypothesis should bear fruit, it ought to modify the practice of breeders 

 to a considerable extent. 



The reason for its inclusion in this discussion is because the writer is of opinion 

 that the ideas and principles that activate enlightened breeders are always worthy of 

 consideration, even though the scientist is unable to prove or disprove them. And 

 in this case facts which support the theory of the practical breeder have undoubtedly 

 been obtained. Statistics in themselves can prove nothing, but placed alongside 

 tangible facts they become alarmingly suggestive. 



Thanks. 



The writer wishes to thank all those who have generously given that help without 

 which the facts and figures would not have been assembled. To Mr. J. S. Gordon, 

 of the Ministry of Agriculture in Northern Ireland, he is particularly indebted, for 

 the study owes its origin to his ideas. Thanks are due to the Jersey Cattle Societies 

 of both jersey and England for the loan of the herd books, as well as for help in other 

 directions, to the Ministry of Agriculture for the gift of the ' Registry,' and also to 

 Mr. Bruce Ward for particulars about his herd. To Dr. H. Comer the writer is 

 grateful for his suggestions and for his patience and forbearance throughout a lengthy 

 correspondence. 



And finally the writer gladly acknowledges the work of Mr. J. R. Brown, B.Sc. 

 (Agr.), of the Nigerian Agricultural Service, who did all the statistical work, analysed 

 the pedigrees and calculated the coefiScients. The writer regrets that Mr. Brown was 

 unable to conclude this investigation himself. 



